1188 



TUNICATA. 



simple (fig. 778). Dendrodoa closely agrees 

 with Cynthia in its branchial reticulations and 

 its digestive apparatus ; but, as Mr. Mac Leay 

 has observed, of the two ovaries possessed by 

 Cynthia, only one, and that the left, is found 

 in Dendrodoa, whilst the right ovary alone is 

 present in Pandocia. 



Genus Chelyosoma, Broderip and Sowerby. 

 Body depressed, oblong, fixed, sessile ; test 

 coriaceous, its upper surface consisting of 

 eight somewhat horny, angular plates; ori- 

 fices small, prominent," perforating the plated 

 surface, each surrounded by six triangular 

 valvules (fig. 767.) ; branchiae plicated ; ten- 

 tacles simple. 



Fig. 767. 



Chelyosoma Macleayanum. (After Broderip and 

 Sowerby.') 



a, branchial orifice ; b, anal orifice ; c, coriaceous 

 envelope of the sides ; d, stone to which the animal 

 is fixed. 



To the Ascidiadce we may provisionally join 

 the following obscure form, occurring on the 

 coasts of South America : 



Genus Fodia, Bosc. Body oval, mammil- 

 lated, divided throughout its length by a vertical 

 partition, which contains the stomach, into two 

 unequal tubes open at each end by an orifice, 

 the superior aperture rather depressed and ir- 

 regularly toothed, the inferior bordered by a 

 circular collar forming a sucker, and serving 

 to attach the animal to extraneous objects. 



Genus JBoltcnia, Savigny ; synonym, Asddia, 

 Auct. Body more or less globular, fixed, pe- 

 dunculated, attached sometimes to the stem 

 of another individual; test coriaceous; ori- 

 fices lateral, and each cleft into four rays ; 

 branchial sac longitudinally plicated ; sur- 

 mounted by a circle of compound tentacula. 



Genus Cystingia, MacLeay. Body glo- 

 bular, fixed, pedunculated ; test subcoriaceous ; 

 branchial orifice quadrifid, lateral ; anal irre- 

 gular, terminal ; branchial sac plicated ; tenta- 

 cula compound. 



Genus Bipapillaria, Lamarck. Body more 

 or less globular, free, pedunculated ; test mem- 

 branous ; the extremity of the body opposite 

 to the attachment of the peduncle bearing two 

 equal, conical papillae, having their apices per- 

 forate ; each orifice furnished with three very 

 short, stiff, setaceous, retractile tentacles.* 



* This obscure genus was established by Lamarck 

 from a description and figure in Peron's MSS. 



Family CLAVELLINID^E, E. Forbes. Syno- 

 nyms : Ascidice, Auct. ; Tcthyes simples^ pars, 

 Savigny ; Ascidiens sociales, Milne-Edwards ; 

 PerophorienSy Van Beneden. 



Body compound, fixed ; animals connected 

 by creeping, tubular prolongations of the com- 

 mon tunic, through which the blood circu- 

 lates. This family comprises two genera: 



Genus Clavellina, Savigny ; synonym, As- 

 cidia, Auct. Body elongated, erect, more or 

 less pedunculated ; test smooth and trans- 

 parent ; branchial and anal orifices without 

 rays ; thorax usually marked with coloured 

 lines (fig. 768.). 



Fig. 768. 



Clavellina producta. Group of two adult and se- 

 veral young individuals, magnified about five times. 

 {After Milne- Edwards.} 



c, branchial orifice ; e, branchiae ; A, cloaca ; t, anal 

 orifice; k, inner tunic or mantle; I, stomach; TW, 

 intestine ; w, termination of the anus and oviduct in 

 the cloaca ; o, the heart ; p, ovary ; p, ova ready 

 to pass into the cloaca ; u, ui, ", reproductive buds, 

 in different degrees of development, springing from 

 the abdomen of the adults. 



Genus Perophora, Wiegmann.* Individuals 

 pedunculated, stiborbicular, compressed ; tho- 

 rax not lineated by granular bands. 



* This curious little social Ascidian was first 

 described and illustrated by Mr. J. Lister, in a 

 paper " On the Structure and Functions of tubular 

 and cellular Polypi and of the Ascidiae," Philos. 

 Trans. 1834. Lister gave no name to the animal, 



