98 DR W. A. HERDMAN ON 



(see PI. XVI. fig. 1), this species shows resemblances to Ascidia lata* and 

 Ascidia meridionalis,f but it differs greatly from both these species in internal 

 structure. 



The shape of the body -when the test is removed (PI. XVI. fig. 3) is remark- 

 able on account of its great antero-posterior elongation, and the position of the 

 stomach and the intestine so far from the posterior end. The appearance 

 presented by the body when seen from the left side suggests that this peculiar 

 relation is caused by the branchial sac having extended posteriorly beyond the 

 stomach. 



The muscular pad at the base of the branchial siphon, from the lower edge 

 of which the tentacles spring (PI. XVI. fig. 6), is very strong. The tentacles 

 are large, and so numerous that their bases touch. 



The dorsal tubercle (PL XVI. fig. 6) is peculiar, inasmuch as the left horn 

 is bifurcated ; however, this is very possibly merely an individual variation. 



With the exception of Ascidia meridionalis, obtained during the " Challenger" 

 expedition at 600 fathoms, off the south-eastern coast of South America, the 

 present species was found at the greatest depth from which the genus Ascidia 

 has been recorded. 



Ascidia virginea, O. P. Muller (PL XVII. figs. 3 and 4). 

 ( = Ascidia sordida, Alder & Hancock, Cat. Mar. Moll. Northumb., &c.) 



At first sight, and after a hasty examination, I was inclined to consider this 

 specimen as a new species, but after a more careful investigation of its anatomy 

 I prefer to regard it as merely an abnormally-shaped individual of Ascidia 

 virginea. If this form should be found to occur with sufficient frequency it 

 might be distinguished as variety pedunculata. I remember dredging a 

 similar individual a few years ago in the Firth of Forth, but cannot now 

 find the specimen in my collection. 



The body is pyriform, shortly pedunculated, and attached by the posterior 

 end (PL XVII. fig. 3) ; it is slightly compressed dorso-ventrally. The anterior 

 end is narrow, but widens rapidly, especially on the right side ; the widest point 

 is reached at a little more than one-eighth of the distance from the anterior to 

 the posterior end. The anterior half is moderately swollen, the posterior 

 half is much narrower, and forms a short stalk. The apertures are both near 

 the anterior end, not distant, sessile, but conspicuously lobed. The surface 

 is rather irregular, but smooth ; it is somewhat incrusted by foreign objects. 

 The peduncle is slightly enlarged at its lower extremity to form a disc of 



* HSBDMAN on British Tunicata, Linn. Soc. Jour., ZooL, vol. xv. p. 277. 



t Hhbdman, Report upon the Tunicata of the " Challenger" Expedition, part i. p. 207. 



