THE "TKITON" TUNICATA. 97 



aperture on dorsal edge, halfway from anterior to posterior end, sessile, wide, 

 indistinct lobed. Surface even and soft, but finely roughened all over. Colour 

 greyish-brown. 



Test soft, cartilaginous, not stiff; thin on right side, much thicker on left, 

 especially at the area of attachment, where it increases to 1*5 cm. ; smooth and 

 glistening on inner surface ; clear and transparent in section. Vessels not con- 

 spicuous. 



Mantle. — Shape long and narrow ; siphons long, especially atrial, which is 

 placed nearly halfway down the dorsal edge ; musculature strong on right side, 

 almost absent on left, where the mantle is thin and membranous; sphincters 

 moderately developed. 



Branchial Sac rather delicate and not plicated. Transverse vessels alter- 

 nately larger and smaller, the larger ones with broad membranes hanging 

 from them. Internal longitudinal bars narrow, bearing large curved papillae 

 at the angles of the meshes. Stigmata long and narrow, usually five in each 

 mesh. 



Dorsal Lamina narrow, slightly ribbed transversely, and toothed on the 

 margin ; double for a short distance at the anterior end. 



Tentacles numerous, of several sizes, some very long (up to 1*5 cm.), stout 

 at the base. 



Dorsal Tubercle small, irregularly ovate in outline, aperture anterior, horns 

 not coiled. 



Alimentary Canal not large, placed on the left side of the body about the 

 middle. (Esophageal aperture two-thirds of the way down the dorsal edge of 

 the branchial sac ; stomach irregularly pyriform ; intestine rather wide, and 

 forming a narrow loop. 



Genitalia in intestinal loop, Spermatic vesicles extending over the greater 

 part of the intestine. Vas deferens wide and prominent, running along the 

 posterior and dorsal side of the rectum towards the atrial aperture. 



Three large specimens and one small one of this new species of Ascidia 

 were obtained in the second haul of the dredge at Station 13 (31st August 1882, 

 in the centre of the " warm area "), from a depth of 570 fathoms, bottom ooze. 

 All of the specimens were more or less incrusted, especially upon the left side, 

 with fragments of sponges and worm tubes ; one of them had a few specimens 

 of a small Tubularian zoophyte adhering, while the smallest individual had 

 several specimens of Anomia ephippium attached to its test. 



The largest specimen is 13 5 cm. in length and 8 cm. in breadth, the smallest 

 5 cm. in length and 3 cm. in breadth. The remaining two are 9*5 cm. and 

 10*5 cm. respectively in length, while both measure 6*5 cm. across at the widest 

 point. In general shape, and especially in the position of the atrial aperture 



