96 BBIT1SH TUNICATA. 



be considered the homologues of the primary vessels. 

 The longitudinal rods are wide and numerous, there 

 being eight or nine on the folds, and three or four 

 between them ; they are attached to the small trans- 

 verse vessels. The endostvle is wide, delicate, and soft. 

 The branchial tubercle (PL XL VIII, fig. 8) is small 

 with the extremities turned inwards or only slightly 

 convoluted, and is widened transversely. The oral 

 filaments or tentacles (PL XL VII I, fig. 8), from twenty 

 to thirty, are placed on a ridge ; they are small, not 

 compressed, and have their points attenuated. The 

 alimentary canal forms a loop which extends nearly 

 the length of the pallial sac ; the calibre is about equal 

 throughout; the stomach is chiefly distinguished by 

 the presence of the liver, which is of a pale greenish 

 colour, and divided into two unequal, dense, irregular, 

 lobes; its minute structure is composed of small, 

 branched tubules, closely packed together and en- 

 veloped in a common delicate membrane. The border 

 of the anus is smooth. 



The reproductive organs are two irregularly- 

 elongated, dense, and somewhat lobed masses, con- 

 taining both elements ; the ducts issue from the 

 anterior extremity; they are short, somewhat reflected, 

 and stand up from the surface of the mantle. The 

 right-hand mass lies within the intestinal loop ; the 

 left near to the endostvle. 



t/ 



Professor E. Forbes mistook this species for an 

 Ascidia. His figure in consequence represents the 

 apertures with too great a number of segments. There 

 are certainly only four in each orifice. 



The beautiful star - like hairs of the test (see 

 PL XXX, fig. 10), best seen in adult and well- 

 developed specimens, distinguish this interesting- 

 species from its congeners. It is also peculiar in 

 the arrangement of the meshes of the branchial sac, 

 the smaller vessels of which are here transverse, while, 

 with one exception, in all the other known species 

 of the genus as well as in those of Ascidia, they are 



