Proc. malac. Soc. Lond. { 1973) 40, 287.

TWO NEW GENERA OF PL AN ORB I DAE FROM AFRICA AND MADAGASCAR

D . S. B R O W N AND G. MANDAHL-BARTH British Medical Research Council, cjo Experimental Taxonomy Unit, Zoology Department, British Museum (Natural History), onodd rm tp/mlu.xodorasog a Uiest o Roe sad n oebr 3 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded London, S.W J 5BD, and, Danish Bilharziasis Laboratory, D K 2920 Charlottenlund, Denmark

Some small species of Planorbidae living in Africa have been classified according to shell characters in either Anisus Studer or Gyraulus Charpentier, both genera based upon European species. The structure of the penis of some of these African and Madagascan forms is so different from that of the European species that they may be regarded as belonging to distinct groups for which generic names are now proposed. It has been widely accepted that Anisus is based on Helix spirorbis Linnaeus (Pilsbry, 1934; Baker, 1945) having slowly increasing whorls and a wide umbilicus, as does the closely related A. vortex (L.) (Fig. la). The type species of Gyraulus, G. albus Muller, has more rapidly increasing whorls and a small umbilicus (Fig. lb). These two groups have similar anatomical features, including a sclerotized dagger-like penial stylet with a bulbous base and long ‘blade’ (Fig. 2a-g; see also Wright, 1963, Fig. 30 and Meier-Brook, 1964, Fig. 25). Nonetheless, Baker (1945) concluded that ‘the genera should undoubtedly be separated on conchological grounds alone’. In some African species previously classified in Anisus, the sclerotized part of the penis is very different and was first described for A. natalensis (Krauss) in which the penis becomes progressively sclerotized towards the tip, where there are backwardly- pointing spines (Wright and Brown, 1962). Subsequent investigation has shown that this type of penis, with or without spines, is also present in many of the East African species classified in Gyraulus by Mandahl-Barth (1954). A new genus is proposed for this group which, so far as is known, is restricted to Africa. Other African species previously classified either in Anisus or in Gyraulus possess yet another kind of penis, having a very small stylet attached to the tip (Fig. 3i, j) (Binder, 1958; Demian, 1962; Wright, 1963). This group is now recognized as a new genus, divided into two subgenera, the one containing African species and the other a highly distinctive form from Madagascar.

CERATOPHALLUS N EW G E N U S Small discoidal Planorbidae, usually not exceeding 8 mm in diameter, having the penis progressively sclerotized towards the tip, which may bear spines (Fig. 3a-h, 4a). 288 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY onodd rm tp/mlu.xodorasog a Uiest o Roe sad n oebr 3 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded

F i g . 1. Some representative shells of Anisus, Gyraulus, Ceratophallus new genus and Afrogyrus new genus. The scale line represents 2 mm (a - e, g) or 4 mm (f). (a) Anisus vortex, Leicester­ shire, England; (b) Gyraulus albus, Leicestershire, England; (c) G. comollyi, Vereeniging, Transvaal Province, South Africa. Paratype; (d) Afrogyrus (Hovorbis) Irivialis, Ambositra, Madagascar; (e) Ceratophyllus natalensis, Umvoti river, Natal Province, South Africa; (f) C. bicarinatus, Lake Awasa, Ethiopia; (g) Afrogyrus (Afrogyrus) corelus, Lake Zwai, Ethiopia. Note: the illustrations do not show details of surface ornamentation and only the more prominent growth ridges are indicated. BROWN AND MANDAHL-BARTH: NEW GENERA OF PLANORBIDAE 289 The male aperture is at, or near the penis tip. The penis sheath lacks flagella; the preputium is without external accessory structures and there are no conspicuous internal lobes. Numerous prostatic lobes (about twenty) are borne on a separate duct opening into the vas deferens. The blood is reddish in those species that have been examined. The pseudobranch is a simple lobe lacking any ridge or lamella on the dorsal surface, where the anus opens near the tip. The spermatheca is ovoid and usually shorter than its duct. The shell varies widely in form (Fig. le, f; see also

Mandahl-Barth, 1954, Figs. 40, 41); it may be depressed with slowly increasing whorls 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded and a wide umbilicus (as in C. natalensis), the whorls may increase more rapidly and be relatively high with pronounced angulations (C. bicarinalus), and the last whorl may descend producing a concave underside (C. concavus, C. crassus). More or less regular transverse ribs may be present (C. bicarinatus) and spiral sculpture is well developed in several species. Seven species assigned to the new genus are listed in Appendix 1.

Type species Planorbis natalensis Krauss, 1848; 83, Plate V, Fig. 9. Umgeni valley, Natal Province, South Africa.

Diagnosis Ceratophallus is distinguished from all other Planorbidae by the long, progressively sclerotized distal part of the penis, through which the vas deferens passes to the near terminal male aperture.

Derivation Cerato- (horny), -phallus (penis). Since no description has yet been published of the anatomy of Planorbis natalensis from near the type locality in South Africa, some features will now be described of snails collected from the Umvoti river at the road bridge between New Hanover and Grey town, Natal Province (D.S.B. No. 122, 21 February 1964) a locality situated about 22 miles north of the Umgeni River. The shell (Fig. le) resembles that described by Krauss (1848) having an almost horizontal last whorl and a flattened underside. A dissected specimen of 4-4 mm diameter had a relatively large copulatory organ nearly 2 mm long (Fig. 3a), with the distal part of the penis sclerotized and bearing spines at the tip (Fig. 4a). Nineteen prostatic lobes arose from a separate prostatic duct; the spermatheca was ovoid and slightly shorter than its duct. The pseudobranch lacked any ridge on the dorsal surface. Ceratophallus differs from Anisus and Gyraulus (Fig. 2) in the manner of develop­ ment of the penial stylet as well as in its structure. In Gyraulus the whole stylet is formed simultaneously, and after formation advances to a protruding position (Hubendick, 1958), whereas in Ceratophallus sclerotization appears to take place gradually, beginning in small snails in the cells lining the terminal part of the vas deferens. These differences seem to be highly significant and there is no obvious homology between the two sclerotized structures. 290 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY The geographical range of Ceratophallus includes Eastern Africa from Ethiopia (Eritrea) to Gape Province in South Africa, and extends westwards to Chad and the lower Congo (Fig. 5). A number of species with distinctive shells and having restricted distributions occur in Eastern Africa, particularly in association with lakes Albert and Victoria. The rapidly increasing whorls of these forms (bicarinatus, concavus, crassus, kigeziensis, kisumiensis, subtilis) led to their earlier classification in Gyraulus (Mandahl-Barth, 1954). In contrast is the extensive range of C. natalensis, found in a variety of habitats including temporary pools. In Ethiopia, C. natalensis

is so variable as to suggest the existence of a species group (Brown, 1965) and further 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded analysis of variation over a greater geographical area is desirable.

AFROGYRUS NEW GENUS Small discoidal Planorbidae not exceeding 10 mm diameter, having a very small, simple stylet (less than 10 fim) attached to the tip of the penis distally to the male aperture (Fig. 4b). The penis sheath lacks flagella; the preputium is without external accessory structures and there are no conspicuous internal lobes. The blood is reddish in those species that have been examined and the pseudobranch is a simple, pointed lobe with the anus opening dorsally near the tip. Whorls increasing slowly, with or without fine spiral sculpture.

Type species Planorbis coretus De Blainville, 1826; 230. Podor, Senegal.

Diagnosis Afrogyrus is distinguished from all other Planorbidae with the exception of Armiger, by the possession of a very small, simple stylet, the absence of flagella from the penis sheath, and the lack of accessory structures and conspicuous internal lobes attached to the preputium. In Afrogyrus, the shell has showly increasing whorls, whereas in Armiger the whorls are rapidly increasing, depressed and commonly ornamented with prominent, widely-spaced ribs.

Derivation Afro- (African), -gyrus (a circle or ring).

Fio. 2. Copulatory organs of various species of Anisus and Gyraulus drawn by camera lucida to show the penis lying within the penis sheath but no other internal details, (a) Anisus vortex, Klampenborg, Denmark; (b) A. leucostomus, Klampenborg, Denmark; (c) A. spirorbis, Eskemose Wood, Denmark; (d) A . conlortus, Samso Island, Denmark; (e) Gyraulus albus, Odense river, Funen Island, Denmark; (f) G. lam s, Danmarks Akvarium; (g) G. acronicus, Brande river, Jutland, Denmark; (h) G. convexiusculus, Sayadebad, Afghanistan; (i) G. ehrenbergi, near Damietta, Egypt; (j) G. coslulatus, Darfur, Sudan; (k) G. costulatus, Lira, Uganda; (1) G. con- nollyi, Swaziland. BW, Position of attachment to body-wall; PE, penis; PR, preputium; PS, penis sheath; RM, retractor muscle; ST, stylet; VD, vas deferens. *2 292 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY

AFROGYRUS (AFROGYRUS) NEW SUBGENUS Rarely exceeding 6 mm diameter, with many whorls (5 whorls at 5-5 mm diameter in A. coretus) and a wide umbilicus (Fig. lg). Transverse sculpture consists of fine irregular ribs and fine spiral ridges may be present. There may be a single prostatic diverticulum from the male duct, though usually a few prostatic lobes are present and the unusually large number of thirteen has been recorded for A. misellus. The spermatheca is ovoid or more elongated and is usually shorter than its duct. Three species belonging to this subgenus are listed in Appendix 1. 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded

Diagnosis Species of Afrogyrus reaching a small size, having irregular transverse sculpture, few prostatic lobes and a normal spermatheca. The range of Afrogyrus (Afrogyrus) probably includes most of Africa (Fig. 6) as these small snails are doubtless often overlooked. A coretus probably extends south­ wards to Natal Province, being recorded according to shell characters (Brown, 1967). The shell may be difficult to distinguish from young specimens of Ceratophallus natalensis, though at a given number of whorls the shell is less high than that of C. natalensis.

AFROGYRUS (HOVORBIS) NEW SUBGENUS The single known species is comparatively large, completing five whorls at 9 mm diameter (Fig. Id). The depressed last whorl has an angulation bearing a fringe of periostracum. Fine, regular transverse ribs are present. The penial stylet has short basal projections (Fig. 4c). About twenty prostatic lobes arise from a separate prostatic duct. Neither a spermatheca nor a spermathecal duct have been observed (Fig. 4d), though a vaginal swelling is present.

Type species Planorbis trivialis Morelet, 1860; 97, Fig. vi, 7. L’lle Mayotte and the north-west coast of Madagascar.

F i g . 3. Copulatory organs of species belonging to the new genera Ceratophallus and Afrogyrus drawn by camera lucida to show the penis lying within the penis sheath but no other internal details, (a) Ceratophallus natalensis, Umvoti river, Natal Province, South Africa; (b) C. natalensis, Salisbury, Rhodesia; (c) C. natalensis, Lake Chad; (d) C. bicarinatus, Lake Albert (type series); (e) C. kigeziensis, Victoria Nile at Bujagali, Uganda; (f) C. concavus, Victoria Nile at Bujagali, Uganda (type series); (g) C. crassus, Hippo Bay, Lake Victoria, Uganda (type series); (h) C. subtilis, north of Dagusi Island, Lake Victoria, Uganda (type series); (i) Afrogyrus (Afrogyrus) oasiensis, Dahkla Oasis, Egypt; (j) A. (Afrogyrus) coretus, Lake Chad; (k) Afrogyrus (Hoiorbis) trivialis, Madagascar, bw, Position of attachment to body-wall; PE, penis; PR, preputium; PS, penis sheath; RM, retractor muscle; SC, sclerotization; VD, vas deferens. BROWN AND MANDAHL-BARTH: NEW GENERA OF PLANORBIDAE 293 Downloaded from http://mollus.oxfordjournals.org/ at University of Rhode Island on November 13, 2015 13, from November http://mollus.oxfordjournals.org/Rhode Island on of Downloaded University at 294 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY onodd rm tp/mlu.xodorasog a Uiest o Roe sad n oebr 3 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded

F i g . 4 . (a)-(c) The structure of the penis lip. (a) Ceratophallus natalensis Umvoti river, Natal Province, South Africa, (b) Afrogyrus corelus Lake Zwai, Ethiopia, (c) A. trivialis Ambositra, Madagascar. SC, Sclerotized wall of penis; SO, soft tissue; ST, stylet; VD, opening of vas deferens, (d) The genital organs of A. trivialis. B\V, Body-wall; C, copulatory organ; O, ovo- testis; P, prostatic lobes; RM, retractor muscle; S, swelling in vagina; SD, sperm duct; SV, seminal vesicle; U, uterus. BROWN AND MANDAHL-BARTH: NEW GENERA OF PLANORBIDAE 295 Diagnosis This subgenus differs from Afrogyrus (Afrogyrus) in the comparatively large size, the presence of basal projections from the penial stylet, and the absence of a normal spermatheca and duct.

Derivation Hov- (Hova, the indigeneous people of Madagascar), -orbis (a circle). onodd rm tp/mlu.xodorasog a Uiest o Roe sad n oebr 3 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded Material examined Madagascar : Ambositra, Maintirano, Farafangano district. The shells examined conform to the original description of Planorbis trivialis in the comparatively large size (type specimen of 7 mm diameter and five whorls), the angular periphery and the presence of fine transverse ribs. Planorbis crassilabrum Morelet (1860), which has page priority, was described from a smaller shell (5 mm diameter) with a rounded periphery and smooth whorls, and possibly is a distinct species. The absence of the spermatheca and its duct was confirmed in twelve specimens from three localities. The condition does not seem to be related to a stage of sexual activity, so far as can be judged from the size range of snails examined (4-G-9-2 mm diameter). No parasites were observed that might have affected development of the reproductive system, which appeared otherwise normal. We observed a swelling in the upper part of the vagina near the position where the spermathecal duct is normally attached in the Planorbidae (Fig. 4d). Serial sections made of two specimens showed an undulating thickening of the internal wall corresponding to the external swelling. The thickening is largely composed of muscular tissue that is continuous with the muscular layer in the wall of the vagina. In one specimen a brownish mass, possibly a spermatophore, was present in the swelling, which presumably serves the function of the normal spermatheca. It is interesting to compare this structure with the vaginal pouches and corrugations present in some species of Biomphalaria (Barbosa et al., 1968), though in these snails the spermatheca appears to be normally developed. In an account of the anatomy of ‘Anisus crassilabrum'1 from Madagascar, Star- miihlner (1969) illustrated an apparently normal spermatheca and duct. Professor Starmiihlner has kindly allowed us to examine some of these specimens, which have shells similar to though smaller than our Afrogyrus trivialis and likewise have a vaginal swelling but no separate spermatheca. It appears that the vaginal swelling was interpreted as a spermatheca by Starmiihlner. Further detailed studies of shells and anatomy are necessary to decide the relationship between crassilabrum and trivialis. _ Another possibly related species occurs on Madagascar recorded as ‘Gyraulus apertus (Martens)’ by Starmiihlner (1969), according to whom the spermatheca is normal, and the penial stylet is similar to that of Gyraulus costulatus (though this is not clear from the diagrammatic illustration). Shells kindly provided by Professor 296 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY

2 0 10 0 10 20 3 0 40 5 0 onodd rm tp/mlu.xodorasog a Uiest o Roe sad n oebr 3 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded

10 0 . 10 2 0 3 0 4 0 5 0

F ig . 5. The range of Ceratophallus new genus indicated by the distribution of C. natalensis. This figure and Fig. 6 are based on material examined by the authors.

Starmuhlner have a remarkably high whorl and a very small umbilicus and appear to represent an undescribed species. It is difficult' to relate this Malagasy form to Von Martens’ species, which was first found in Lake Edward in East Africa and cannot be identified with certainty from the original account (Mandahl-Barth, 1954 : 93-94). BROWN AND MANDAHL-BARTH: NEW GENERA OF PLANORBIDAE 297

20 10 . 0 10 20 30 40 5 0 onodd rm tp/mlu.xodorasog a Uiest o Roe sad n oebr 3 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded

1______1______1____ V I I i 1 0 . 0 . 10 2 0 3 0 4 0 50

F ig . 6. The range of Afrogyrus new genus in Africa indicated by the distribution of A . corelus. Localities shown in Madagascar for A. trivialis include those from which animals have been dis­ sected and others from which only shells have been examined.

DISCUSSION Ccratophallus is outstanding among discoidal Planorbidae and possibly is unique in the entire family, by virtue of the progressive sclerotization of the penis towards the tip, and the presence of terminal spines in some species. The anatomical characters seem peculiar to an African branch of planorbid evolution in which considerable radiation in shell form has occurred, with lacustrine species tending to have angular 298 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY whorls and a concave underside as do lacustrine forms belonging to other discoidal genera of Planorbidae (e.g. the Biomphalaria choanompliala group). The present segregation of so-called ‘Anisus’ of Africa into different genera is in agreement with the concept of Baker (1945) who regarded Anisus as a European group extending eastwards to Siberia and southwards to Algeria. Although the conchological differences between Anisus and Gyraulus are scarcely adequate generic characters, Anisus may be usefully maintained for the palaearctic group of planorbids having a dagger-like penial stylet and many slowly increasing whorls. The species known to have these characters (including the subgenera Bathyomplialus and 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded Spiralina) are listed in Appendix 2. Species of Gyraulus from Europe, Asia and Africa having relatively rapidly in­ creasing whorls and known to have a dagger-like penial stylet are listed also in Appendix 2. Though the range of the genus includes the whole of Africa, there appear to be only two species south of the Sahara, the widely distributed G. costulatus, and G. connollyi known only from the highveld of South Africa (Brown and Van Eeden, 1969). Species with the same kind of stylet are found also in North America (Baker, 1945) and in New Zealand (specimens kindly supplied by Dr W. F. Ponder). The anatomy has yet to be examined of the many species from other regions described on the basis of conchological characters, though evidently the genus has a very exten­ sive, if not cosmopolitan, distribution. The generic position of Planorbis riparius Westerlund of northern Europe, sometimes classified in Gyraulus, is uncertain; a small ‘papilla’ at the tip of the penis resembling the small stylet of Armiger crista was described by Odhner (1956), but according to Hubendick (1957) the sclerotized part of the penis is long and extends both proximally and distally from the male aperture. This structure requires further investigation. The Planorbidae were divided by Hubendick (1955) into the Bulininae and the Planorbinae, the latter including four tribes based on Planorbis, Helisoma, Biomphal­ aria and Segmentina. In the Planorbis tribe, containing genera Planorbis, Anisus, Gyraulus, Armiger and Choanomphalus, the penial stylet present in the last four genera was stated (Hubendick, 1955 : 529) to be ‘abruptly delimited from the non- chitinised part of the penis’. This is not so in Ceratophallus, which seems to belong to the Planorbis tribe, being distinguished from the tribes of Helisoma and Segmentina by the lack of flagella and the simple internal structure of the preputium, and differing from Biomphalaria in the presence of a separate prostatic duct. As anatomical features become better known, it is likely that considerable modifications of earlier concepts of groupings of genera within the Planorbidae will be necessary. The discoidal Planorbidae occurring in the Palaearctic and Ethiopian regions and southern Asia comprise in addition to Ceratophallus and Afrogyrus, the Planorbis and Segmentina tribes of Hubendick (1955) and the genera Planorbarius and Biomphalaria. Members of the Segmentina tribe are recognizable by the rapidly in­ creasing and usually septate whorls, and there may be one or more flagella attached to the copulatory organ. (In Lentorbis where shell septa and flagella are absent there is a large descending lobe within the preputium.) The remaining genera may be distinguished by means of the following key. BROWN AND MANDAHL-BARTH: NEW GENERA OF PLANORBIDAE 299 1. No separate prostatic d u c t...... Biomphalaria (Africa, Arabia, Neotropics) Separate prostatic duct present (sometimes with a single diverticulum) . . . 2 2. Prostate forms a compact o r g a n ...... Planorbarius ■ (Palaearctic) Prostate consists of a single diverticulum or a row of d iv e rtic u la ...... 3 3. Penis not sclerotized and lacking a stylet or cuticular cap, male aperture term inal...... Planorbis 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded (Palaearctic including North Africa) Penis partly sclerotized or with terminal stylet or cuticular c a p ...... 4 4. Penial stylet with distinctly bulbous b a s e ...... 5 Penis progressively sclerotized towards the tip, or with small stylet (10 ycm) lacking bulbous b a s e ...... 6 5. Whorls increasing slowly...... Anisus (Palaearctic including Siberia and north-west Africa) Whorls increasing r a p i d l y ...... Gyraulus (cosmopolitan) 6. Penis progressively sclerotized d istally ...... Ceratophallus Penis with small stylet attached distally to male a p e r tu r e ...... 7 7. Whorls increasing rapidly, commonly ornamented with conspicuous transverse r i b s ...... Armiger ■ (Europe, Siberia, Ethiopia) Whorls increasing slowly, without conspicuous r i b s ...... 8 8. Small snails usually less than 6 mm diameter with normal s p e r m a th e c a ...... Afrogyrus (Afrogyrus) (Africa) Larger snails reaching 9 mm diameter, lacking a separate sperm atheca...... Afrogyrus (Hovorbis) (Madagascar)

SUMMARY A new genus Ceratophallus is proposed for small, discoidal Planorbidae from Africa, having the penis progressively sclerotized towards the tip, which may bear spines. The male aperture is terminal. The seven known species were classified previously, acording to shell characters either in Anisus or Gyraulus, genera based upon European species possessing a dagger-like penial stylet with a bulbous base clearly delimited from the penis tissue and attached distally to the male aperture. The structure and manner of development of the two types of penis seem to be fundamentally different. Ceratophallus is widely distributed in Eastern Africa, inhabitats a variety of water­ bodies and has produced a number of lacustrine species having characteristic shells. 300 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY A new genus Afrogyrus is proposed for small, discoidal Planorbidae from Africa and Madagascar having a very small stylet on the penis tip, attached distally to the male aperture. Previously the four species recognized were classified in Anisus. Species from the African mainland are placed in the subgenus Afrogyrus, while a subgenus Hovorbis is proposed for A. trivialis from Madagascar, unique among Planorbidae in lacking a separate spermatheca and spermathecal duct. The recognition of these distinct African branches of planorbid evolution allows

the restriction of the genus Anisus to comprise species having a dagger-like stylet and 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded many slowly increasing whorls; the range of the group is Palaearctic including Siberia and North Africa. Anisus is anatomically similar to Gyraulus, which contains species with comparatively rapidly increasing whorls and has a nearly cosmopolitan distri­ bution including most of Africa.

A P P E N D IX 1 Species assigned to the new genera Ceratophallus and Afrogyrus according to the structure of the penis in material examined by the authors or satisfactorily described in the literature.

Ceratophallus natalcnsis (Planorbis natalensis Krauss, 1848) Type species. Widely distributed in Eastern Africa from Eritrea to Cape Province, and westwards to Chad and the lower Congo. bicarinatus (Gyraulus bicarinatus Mandahl-Barth, 1954) Uganda (Lake Albert), Ethiopia (Lake Awasa), Chad (Lake Chad). concavus (Gyraulus concavus Mandahl-Barth, 1954) Uganda (Victoria Nile at Bujagali and below Owen Falls). crassus (Gyraulus crassus Mandahl-Barth, 1954) Uganda (Lake Victoria in Napoleon Gulf and Hippo Bay, Entebbe). kigezicnsis (Planorbis kigezicnsis Preston, 1912) Uganda (Bujagali), Congo (Goma near Lake Kivu). kisumiensis (Planorbis kisumiensis Preston, 1912) Kenya (Lake Victoria at Kisumu). subtilis (Gyraulus consulatus subtilis Mandahl-Barth, 1954) Uganda (Lake Victoria north of Dagusi Island).

Afrogyrus (Afrogyrus) corctus (Planorbis coretus De Blainville, 1826) Type species. Widely distributed in Eastern Africa from Ethiopia to Natal Province, and in Western Africa including Ivory Coast (‘Gyraulus gibbonsV Binder, 1958). casiensis (Anisus oasiensis Demian, 1962). Egypt (Dahkla Oasis). MANDAHL-BARTH: NEW AFRICAN MOLLUSCS 301 misellus (Planorbis misellus Morelet, 1868) Angola (Wright, 1963).

Afrogyrus (Hovorbis) trivialis (Planorbis trivialis Morelet, 1860 Type species of subgenus. Madagascar (Ambositra, Farafangano district, Maintirano). onodd rm tp/mlu.xodorasog a Uiest o Roe sad n oebr 3 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded A P P E N D IX 2 Species oiAnisus and Gyraulus from Europe, Western Asia and Africa known to have a dagger-like penial stylet with a bulbous base. Based on observations by the present authors, Baker (1945) and Meier-Brook (1964).

Anisus (Palaearctic distributions) Gyraulus A. spirorbis (L.) G. albus (Muller) Palaearctic. A. contortus (L.) G. acronicus (Ferussac) Europe. A. leucostomus (Millet) G. cockburni (Godwin-Austen) Socotra Island. A. vortex (L.) G. connollyi Brown & Van Eeden, South Africa. G. convexiusculus (Hutton) Arabia, Asia. G. costulatus (Krauss) Africa south of the Sahara. G. ehrenbergi (Beck (= mareoticus Innes). Egypt. G. laevis (Alder) Palaearctic including Middle East. G. rossmaessleri (Auerswald) Europe.

REFERENCES

B a k e r , F. C., 1945. The Molluscan Family Planorbidae. University of Illinois Press, Urbana. B a r b o s a , F. S., B e r r y , E. G ., H a r r y , H . W . et al., 1968. A guide for the identification of the snail intermediate hosts of schistosomiasis in the Americas. Pan American Health Organisation, Scientific Publication, No. 168. B i n d e r , E., 1958. Anatomie de Gyraulus gibbonsi Nelson de Cote d’Ivoire. Revue Suisse de Zoologie, 65 301-304. B r o w n , D. S., 1965. Freshwater gastropod Mollusca from Ethiopia. Bulletin of the British Museum (.Natural History), Zoology, 1 2 ,3 7 -9 4 . B r o w n , D. S., 1967. A review of the freshwater Mollusca of Natal and their distribution. Annals o f the X atal .Museum, IB, 477—19 J. B r o w n , D . S. and Van Eeden, J. A., 1969. The molluscan genus Gyraulus in southern Africa. Journal of the Linnean Society o f London, Zoology, 48, 305-331. D e m i a n , E. S., 1962. Anisus oasiensis n. sp. A new planorbid species from Egypt. Arkivfor Zoologi, (2) 15, 149-162 Hubendick, B., 1955. Phylogeny in the Planorbidae. Transactions o f the Zoological Society o f London, 28, 453-542. • Hubendick, B., 1957. On the male copulatory organ in Anisus. Proceedings o f the Malacological Society of London, 32,208-212. H ubendick, B., 1958. The development of the penial stylet in Gyraulus (Mollusca, Pulmonata). Arkiv fo r Zoologi, (2) 11,427—429. K r a u s s , F., 1848. Die Siidafrikanischen Mollusken. Ebner and Seubert, Stuttgart. 302 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY

M andahl-Barth, G., 1954. The freshwater mollusks of Uganda and adjacent territories. Annales du Music Royal du Congo Beige Se'r. 810, Sciences zoologiques, 32, 1-206. M eier-Brook, C., 1964. Gyraulus acronicus and G. rossmaessleri, ein anatomischer Vergleich (Planor­ bidae). Archiv fu r Atolluskenkunde, 93, 233-242. O diin’ER, N ., 1956. Distinctions between Anisus (Armiger) crista (L.) and Anisus (Gyraulus) riparius (W est.) Proceedings o f the Malacological Society o f London, 32, 127. P i l s b r y , H. A., 1934. Review of the Planorbidae of Florida, with notes on the other members of the fam ily. Proceedings o f the Academy o f Natural Sciences o f Philadelphia, 86, 29-70. Starm uhlner, F., 1969. Die Gastropoden der Madagassischen Binnengewasser. Malacologia, 8 , 1-434.

W r i g h t , C. A., 1963. The freshwater gastropod mollusca of Angola. Bulletin of the British Museum 2015 13, November on Island Rhode of University at http://mollus.oxfordjournals.org/ from Downloaded (Natural History), Zoology, 10, 447-528. W r i g h t , C. A . and B r o w n , D. S., 1962. On a collection of freshwater gastropod molluscs from the Ethiopian highlands. Bulletin of the British Museum (Natural History), Zoology, 8, 285-312.