CXIX.-ASCIDIANS FROM MOZAMBIQUE, EAST AFRICA. By R. H. MILLAR, Marine Station, Millport. lNTRODUCTION. A small collection of littoral ascidians (class Ascidiacea; sub-phylum Tunicatal bas been made from various places on the coast of Mozambique, East Africa, by Mrs. M. Kalk of the Zoology Department, the University ofWitwatersrand, and the present paper gives an account ofthe collection. Most of the specimens come from the shores of Inhaca Island (lat. 26° S.) which lies at the mouthof Delagoa Bay and is almost due east of Lourenço Marques. There are also a few specimens from the shores of Mozambique Island (lat. 15° S.) and Santa Carolina (lat. 22° S.). The ascidians of East Africa have already been described by Michaeisen (1918, 1919, 1920, 1921) who summarized previous information and also added new accounts of his own. Systematic list of species. Family Polyclinidae Milne Edwards. Aplidium altarium (Sluiter). A. petrense Michaelsen. A. lubricum (Sluiter). Polyclinum macrophyUum Michaelsen. Family Polycitoridae Michaelsen. Eud·istoma 1·hodopyge (Sluiter). E. mobiusi (Hartmeyer). E. caeruleum (Sluiter). E. paesslerioides Micha.elsen. Clavelina enormis Herdman. Family Didemnidae Verrill. Diplosoma modestum Michaelsen. Didemnopsis sansibaricum Michaelsen. ?Didemmtm psammatodes (Sluiter). Family Ascidiidae Herdman. Ascidia incrassata Heller. A. arenosa Hartmeyer. Family Botryllidae Verrill. Botryllus plan'U8 (Va.n Name). Family Styelidae Sluiter. Symplegma viride Herdman. Styela marquesana Michaelsen. Polyandrocarpa tincta (Van Name). P. inhacae sp. n. A.M.N.H. ser. 12, vol. ix, 58 914 R. H. Millar on Ascidians from Mozambique Family Pyuridae Hartmeyer. Pyura sansibarica Michaelsen. Herdmania momus (Savigny). DESCRIPTION OF SPECIES. Family Polyclinidae Milne Edwards, 1842. Genus Aplidium Savigny, 1816. Aplidium altarium (Sluiter), Fig. I. Amaroucium altarium Sluiter, 1909, p. 105, pl. 5, fig. 9. Aplidium altarium Michaeisen 1919, p. 90. Known Distribution.-South of Ceram, Indonesia ; Zanzibar. Locality.-Mozambique Island ; three colonies. Description.-The colonies are no more than 4 rnm. thick, and the largest one is 1·8 b~I·O"ém. across. After preservation in alcohol the colour is pale pink-grey with lighter spots marking the zooids. There is no obvious arr~ement of the zooids in systems and no cornmon cloaca! openinga are vi~ible to the naked eye. The surface is smooth and the Fig. I. A Aplidium altarium (Sluiter). A, zooid. B, larva. consistency of the colony soft. There is no foreign matter embedded in..Jlt the test or enerusting the surface. In structure the zooids agree closely-~ with Sluiter's and Michaeisan's descriptions. The large number ofJt folds on the stomach is especially characteristic of the species, Michaelsen~!~ having noted 43, and the present material showing 30, 36 and 40 in throoJ zooi"ds examine. d . •.• ··.~~ ~~" ~ A number of zooids were carrying embryos and Iarvm, generally from: ~: one to three in each breeding zooid. The larva me~ures about 0·6 mm1.i R. H. Millar on Ascidians from Mozambique 915 from the end of the papillre to the base of the tail. There are the three papillre as usual in the genus, and four rounded anterior ampullre or vesicles ·detached from the body of the larva. The sensory vesicle contains both ocellus and otolith. A plidium petrense Michaelsen. Aplidium petrense Michaeisen 1919, p. 92, figs. 5-7. K nown distribution.-Zanzibar ; Madagascar. Locality.-Mozambique Island; two colonies. Description.-The larger of the two colonies is 1·1 cm. by 0·5 cm. across and about 0·6 cm. tall. Both colonies are attached to small pieces of algae. The test is smooth, soft and semi-transparent with the zooids showing through. There is no foreign matter. Six pointed lobes surround the atrial opening. There are 24 folds on the stomach. Although my specimens have seven rows of stigmata compared with five found by Michaeisen I think there is little doubt that we are dealing with A. petrense. A Aplidium lubricum (Sluiter). A, zooid. B, la.iva. Aplidium lubricum (Sluiter). Fig. 2. Amaroucium lubricum Sluiter 1897, p. :n. pl. 1, fig. 9, pl. 5, fig. 1. Michaeisen 1919, p. 100. Known distribution.-Durban, Natal. Locality.-Inhaca Island; one specimen. 58* 916 R. H. Millar on Ascidians from Mozambique Description.-The colony is a sheet 5·5 cm. by 2·0 cm. across and 0•6' cm. thick. The test is semi-cartilaginous. The zooids seem to he,' arranged in linear systems but the grouping is not very distinct. Thé ; zooids may reach 4 mm. in length, of which the thorax occupies abou( 1·8 mm. There are eight or nine rows of stigmata. The stomach has · about 16 undivided longitudinal folds. Some of the zooids have larvlé intheatrial cavity. The larva is about 0·4 mm.long from the end ofthe: papilloo to the base of the tail. There are three anterior papilloo. Maily, small detached epidermal vesicles surround the anterior end of the trunk' and extend backwards along the doraal and ventral surfaces. Both ' otolith and ocellus are present. , The zooids of the colony from Inhaca Island agree well -with Sluiter's •-• original description, but the form of the colony and the shape of the} systems are a little different. I do not think that these differences anfJ as important as the ,:r~oints of resemblance, and consider that the identi"" fication is well estaJilished. 8 Polyclinum macrophyllum Michaelsen. A, thorax of a zooid. B, part of gut. C, larva. Genus Polyclinum Savigny, 1816. Polyclinum macrophyllum Michaelsen. Fig. 3. Polyelinwm macrophyUum Michael!en 1919, p. 82, figs. I, 2. Known distribution.-:-Madagascar; W. Australia. Locality.-Mozambique Island ; three colonies. Description.-Tbe colonies are flat,· up to about 4 mm. in ~u • ..,Al .• .,.,~.tii] and dull purple brown. There is little to add to Michaelsen's R. H. Millar on Ascidians from Mozambique 917 description of the zooids. In the present specimens the wall of the stomach bears a. number of small round ma.rks which give the stomach a. slightly areolated appearance but the marks are not raised. Michaeisen described the stomach as smooth-wa.lled. Two of the colonies contain larvre. These maasure a bout 0·4 mm. long from the end of the papillre to the base of the tail. There are, at the anterior end of the trunk, three papillre and four rounded a.mpullre. Both otolith and ocellus are present. Fig. 4. A c Eudistoma rhodapyge (Sluiter). A, small eolony. B, large eolony; C, larva. Family Polycitoridae Michaelsen, 1904. Genus Eudistoma Caullery, 1909. Eudistoma rhodopyge (Sluiter). Fig. 4. Distoma rhodopyge Sluiter 1897, p. 12, pl. 1, fig. 2, pl. 3, figs. 5, 6. Polycitor (Eudistoma) rhodopyge Hartmeyer 1909, p. 1432; Michaelsen, 1919, p. 72. For synonymy see Michaelsen, 1934, p. 141. Known distribution.-Mozambique; Durban; False Bay and Still Bay, Cape Province. Localities.-Inb.aca Isla.nd ; Mozambique Island ; Santa Carolina. Desc1iption.-The collection contains saveral colonies which vary . from closely grouped short conical masses attached by their narrow ends, to taU finger-like inassas fairly widely separated. Most of the colonies are pale translucent pink and the collector's note described some of them as " bright pink (or white)" during life. 918 R. H. Millar on Ascidians from Mozambique According to Michaeisen (1934) this is a very variabie species. It has been described under several names. Amongst the present material the shorter coionies have zooids 2·0 to 2·8 mm. in Iength and the tall :finger-like colonies have zooids reaching 6 mm. in Iength. The zooids have no diagnostic features and show the characters common to the genus. Larvm are present and these range from 0·36 to 0·54 mm. in length. When fully developed the larvre have the three anterior papillre separated by two median ampullre. One doraal and one ventral media:n ampulla are a.Iso present. The cerebral vesicle contains an ocellus and otolith. The larva is quite large relative to the size of the thorax of the zooid and all the breeding zooids that I have seen contain only a single embryo or larva. Fig. 5. EudiBtoma mobiU8i (Hsrtmeyer). Zooid. Eudistoma möbiusi (Hartmeyer). Fig. 5. Colella möbiusi Hartmeyer 1905, p. 396, pl. 13, :figs. 2, 3. Polycitor möbiusi Hartmeyer 1912, p. 305, text-:figs. 1-3, pl. 43, fig. 4. ( Polycitor (Eudistoma) möbiusi Michaeisen 1919, p. 73. ;, K nown distribution.-Tanganyika; Mozambique; Zanzibar; Mauritius ;..,U . Madagascar ; Durban ; Cape Province. · .!i Localities.-Inhaca Isiand, two specimens; Mozambique Island, one'~i specimen. · ;:.~ Description.-The three colonies are all rather small, the largest bein~·.l·~ 1·3 cm. in diameter. The basal area of attachment is :Bat and the uppet• i }!t R. H. Millar on Ascidians from Mozambique 919 surface rounded. There may he a slight subdivision of the colony into indistinct lobes, as in one of the specimens from Inhaca Island. In consistency the test is rather soft or semi-cartilaginous and in colour it has a characteristic green-blue suffusion especially in the upper part. The zooids show through the test as darker green-blue spots. Existing accounts leave little to he added to the description of the zooids. In the present specimens the pigmentation is most intense on the anterior part of the thorax. Some of the zooids are sexually mature, having in the Iower part of the abdomen a compact group of testis follicles and a few large oocytes repreaenting the ovary. Unfortunately no fully developed larvm were present, but the most advanced embryo already had a tail and sensory pigment. The trunk of this embryo measured 2 mm. in length and although the larva when fully differentiated, may be shorter, it is clear that E. möbiusi ~as a very large larva. · Eudistorna caeruleum (Sluiter). Fig. 6. Distoma caeruleum Sluiter 1897, p. 14, pl. 2, fig.