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ON THE STATUS OF THE GENERIC NAMES OF THE GENERA CATRIONA, CRATENA, IIERVIA, RIZZOLIA AND TRINCHESIA. Downloaded from https://academic.oup.com/mollus/article/31/2/52/995003 by guest on 28 September 2021 By "WILLIAM MACNAE, Department of Zoology, Rhodes University, Grahamstown, South Africa. (Read 8 October, 1954) Summary.—The Catriona Winckworth (1941) is synonymous with Trinchesia Pruvot-Fol (1951) but not with Trinchesia von Jhering (1879). It has priority over Trinchesia Pruvot-Fol. The genus Cratena Bergh (1864) is valid and synonymous with Rizzolia Trinchese (1877) but not with Ilervia Bergh (1871). The genus Hervia Bergh (1871) is synonymous with Facelina Alder and Hancock (1855), but not all species oi'IIervia can be included in the latter genus, and these should, therefore, be distributed among other genera, some of which are listed.

Several genera of Nudibranchiate were not clearly defined by the authors who established them. Such genera have been difficult to recognize subsequently unless a species which can be readily identified was designated as type of the genus. As a result there have been included in such genera species which have few or no points in common with the original type species. Such a confusion has long existed in the genus Cratena (see O'Donoghue (1926) and Winckworth (1941)). Into this confusion the genera , Ilervia and Rizzolia have been drawn. The introduction of the genus Cuthona into this muddle is due to Vayssiere (1913), and his use was followed by Baba (1937 and 1938) although the error had been pointed out by O'Donoghue (1926). Baba has in more recent work (1949) conected his mistake. As a matter of fact this error is not surpiising for when Bergh (1864) set up the genus Cratena one of the species he included in it was Cuthona olrikki, and the true identity of this form was not recognized until some time subsequently. The confusion over the other geneia persists. The oldest of them, Cratena, was set up by Bergh in 1864 and Doris peregrina Gmelin 1789 was designated type species. It is irrelevant that the diagnosis given does not apply to the type species and that the the two species (C. hirsuta and C. olrikki) placed in the new genus are not congeneric with the type. The relevant fact is that the species designated as type is one which is capable of recognition and a complete description of it was given by Trinchese (1880) who had (1877) designated it as type species of his genus Rizzolia. It follows, therefore, as has already been pointed out by Winckworth (1941) that Rizzolia is a complete synonym of Cratena which has priority. Unfortunately attention was given, not to Bergh's designation, but to the diagnosis, with the result that the genus Cratena came to contain a variety of species mostly congeneric with one another but not resembling in any particular the type of the genus. Winckworth (1941) separated off these atypical species and proposed for them the name Catriona, designating Eolis aurantia Alder and Hancock as type species. Mme Pruvot-Fol (1951) considers that the name Trinchesia von Jhering MACNAE : OX CATIilOXA, C1UTEXA, UEHV1A, 1UZZ0L1A AND TIUXCUESU 53 (1879) applies to this group and should have priority over Winckworth's name. I dispute this and believe that the name Trinchesia does not apply to these . The name is a nomen nudum or at best a nomen dubium. It ai>pears in a footnote below an account of certain conjectures regarding

the origin of the ncmatocysts in the cerata of Eolids in general. The foot- Downloaded from https://academic.oup.com/mollus/article/31/2/52/995003 by guest on 28 September 2021 note reads:— " Ich benUt^e die Gelegenheit, ura Her mitzutheilen, dass ich in der fiir Nudibranchien offenbar besonders reclien Fauna des Goifes von Neapel u. A. in mehreren Arten cine Gruppe von Aeolidiaden aufgefunden habe, welche, abgesehen von den Penisbewaffnung, nur dadurch von den Galvinen sich unterschieden, dass ihr Eadula einreihig ist. Ich stelle fiir diese Formen zu Ehren des urn die Kenntniss des Aeolidiaden des Mittelmeeres so hoch verdienten Prof. Trinchese die Gattung Trinchesia auf." A tyjje species is not designated, nor is the diagnosis adequate. Such a name might have become valid under the Rules of Nomenclature provided definite animals had been described so that they could be recognized subsequently, and that it had been possible for a reviser to designate one of them as the type species of the genus, von Jhering's definition does not permit of this. An important diagnostic feature of the genus Catriona as defined by Winckworth is the possession of a radular tooth the median cusp of which is less prominent than the lateral denticles. In all species included by Bergh (1882) in the genus Galvina the median cusp is prominent, and even though it may be reduced in size it is never subsidiary to the others as it is in Calriona. I am of the opinion, therefore, that the meaning given to the name by Mme Pruvot-Fol is not that suggested by von Jhering, and that to avoid confusion it is preferable to continue to use the name Catriona for this genus, with Trinchesia Pruvot-Fol 1951, non von Jhering 1879 as a synonym. Eliot (1904) commented that he could see no differences between the genera Ilervia and Rizzolia. Barnard (1927) united the two genera but gives no reason for doing so. Baba (1937 and 1938) also united the two genera but made them sub-genera of Culhona, a mistake he has since (1949) corrected. Mme Pruvot-Fol (1918 and 1951) also considers that these two genera are synonymous, and discards Cralena from the synonymy because the original citation was given in Danish. This course is not permissible. On the other hand Ilervia and Cralena (=Rizzolia are not synonymous. During the course of an investigation of certain South African Eolids it became obvious that the genus Ilervia contained an assemblage of species many of which bear few resemblances to one another. Not having at that time access to Bergh's original descriptions of the genus I communicated my difficulties to Dr Nils Odhner of Stockholm who replied to my inquiry as follows:— " Nobody seems to have observed the meaning of this genus name " (Hervia). " It was established by Bergh in 1871 (brief diagnosis only, a description followed in 1874). The type was modesta n.sp. from the Kattegat, likewise briefly characterized in 1871. In 1874 Bergh described it satisfactorily enough for enabling its identification. He says :— VOL. 31.—DECEMBER 1954. 5 54 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY

' Die Papillen etwas wie bei den Facelinen gestellt. Die Papillenkissen nur unbedeutend liervortretend, langgestreckt, mit kurzen Schragreihen von Papillen besetzt. Die erste Papillenkissen weit vorwarts reichend, zahlte 6 Reihen von denen die zwei hinteren hufeisenformig vereint waren.

Die nachste Kissen zahlte 5 Reihen, von denen die zwei hintersten wieder Downloaded from https://academic.oup.com/mollus/article/31/2/52/995003 by guest on 28 September 2021 in der erwahnten Weise vereinigt waren und in ihrem Bogen die Analpapille aufnahmen.' From these words it is evident that the arrangement of papillae and anus is the one characteristic of Facelina: Hervia, consequently is a synonym of Facelina and further comparison with the description will reveal as probable that H. modesta is an abnormal modification of Facelina drummondi." Critical reading of Bergh's (1874) account of Hervia modesta has convinced me that Dr Odhner's opinion is correct. It is perhaps significant that this species has never been found again in spite of the fact that it came from the Kattegat, an area which is regularly searched by many competent workers. Apart from the type species no others fall within the limits of the genus Facelina. Most of the species of Hervia have the right liver in the form of an arch or horse-shoe, and these seem to fall into two groups :— (i) Some have the right liver in the form of a simple horse-shoe and the posterior branches may have the form of horse-shoes or be single. This group includes H. lineata Eliot 1904, and //. serrala Baba 1949. Both of these show certain similarities to Cralena peregrina, and the former of the two should no doubt be included in the 1949. Both of these show certain similarities to genus Cratena. But the radular teeth of H. serrata suggest a closer relationship to Favorinns, and the arrangement of the " liver " branches is not inconsistent with this genus. However the description given is insufficient to make its systematic position absolutely certain. Mme Pruvot-Fol (1951) suggests that //. herghii Yayssiere 1888, another of these simple forms, is actually an immature specimen of Acan- tho])sole rubrovitlata and she is probably correct. (ii) The second group includes six species:—H. japonica Baba 1937 =(Rizzolia modesta Bergh 1880): //. emurai Baba 1937 ; //. inconspicua Baba 1938; H. ceylonica Farran 1905, Baba 1937 and subsequently (this may not be identical with Farran's species); H. quadricolor Barnard 1927 (? =Rizzolia australis Bergh 1884) and //. rosea Bergh 1888 (? = Rizzolia modesla Bergh 1880). All these are similar in having more than one row of cerata in each limb of the horse-shoes. All have smooth rhino- phores—although they may appear wrinkled in preserved specimens. For this group I have established the genus Godiva (Macnae 1954) with the following diagnosis :— Cleioproct Eolidacea; with the majority of the liver branches in the form of horse-shoes or arches, in which the cerata aie inserted in two or moie series; with smooth rhinophores and with the anterior corners of the foot produced into tentaculiform processes ; with the radula uniseriate, of which the teeth have a prominent cusp and strong lateral denticles; with the penis of moderate length, armed with a single hook or unarmed. Type species, Hervia quadricolor Barnard 1927. The species japonica will now revert to its original name of modesta after inclusion in the new genus.