ASCIDIA ELONGATA. 113 



cles rather distant and pointed. Tentacular filaments 

 numerous, lon'. and slender. Branchial sac with 



O J 



obtuse primary but no secondary papillae, the stomata 

 elliptical. Oral lamina smooth, ribbed, rather narrow. 



Length about two inches ; breadth about half an 

 inch. 



Hab. Deep water ? 



ENGLAND. Sealiam Harbour (Hodge). 

 First record. Hancock, 1870 ; coll. Hodge. 



The test of this species is extremely hyaline, and 

 contains numerous blood-channels, which are minutely 

 subdivided, the ultimate twigs terminating in rounded 

 extremities. 



The mantle is well supplied with delicate muscular 

 fibres, transverse, longitudinal; and diagonal ; but they 

 are not arranged with much order. 



The branchial sac (PI. XVII, fig. 12) is long and 

 narrow, extending the whole length of the body ; it is 

 minutely plicated ; the plica3 are, however, so shallow 

 and obscure that they might easily lie overlooked, but, 

 on examining the outside of the sac, they are obvious 

 enough. The primary vessels are pretty regular ; but 

 the secondary vary considerably, some being very wide, 

 others comparatively narrow, arising from the irregu- 

 larity of the stomata which not only vary in size but 



/ ./ i/ 



also in form. They are usually wide and short, fre- 

 quently sharply pointed at the ends, and sometimes 

 with one end pointed and the other rounded, so as to 

 have an elongated ovate form ; some extend almost 

 the whole breadth of the space between the primary 

 vessels, others not half that space ; their width, form, 

 and irregularity being very characteristic. The papillae 

 on the longitudinal bars where they intersect the 

 primary vessels resemble those of A. aculeata ; but they 

 are shorter, thicker, more obtuse, and the lateral 

 tubercles are less prominent ; the papillary membrane, 

 also, is more extensively developed, and there are no 

 intermediate small papillae. The oral lamina is rather 



8 



