REPORT ON THE TUNICATA. 215 



intestine is largo, but the intestinal loop is rather small. The ovary is considerably 

 branched, and lies chiefly upon the right side of the loop. The spermatic vesicles are of 

 the usual pyriform shape, and are united in twos and threes at the ends of the dichoto- 

 mising vas deferens ; they are found chiefly over the intestine in the lower part of the 

 rectal loop. The genital ducts are conspicuous along the lower edge of the rectum. The 

 renal vesicles cover the greater part of the left side of the stomach. They are large and clear- 

 walled, and contain each one or more spherical concentrically laminated brown concretion-. 



This species somewhat resembles Ascidia virginea, 0. F. Midler, but is undoubtedly 

 distinct from it. That species differs from the present one chiefly in its greater length in 

 proportion to the breadth, its greater number of tentacles, the absence of intermediate 

 papillae on the branchial sac, the shape of the tubercle, and in the condition of the dorsal 

 lamina, — all fairly good characters. 



Three specimens, one of them in good condition (the one figured on PI. XXXII. 

 fig. 7), were obtained from the western end of the Straits of Magellan, at Station 311, 

 January 11, 1876" ; hit, 52° 50' S., long. 73° 53' W.; depth, 245 fathoms; bottom tem- 

 perature, 7° '7 C; bottom, mud; and two, one of them damaged, were obtained off the 

 coast of Buenos Ayres, South America, at Station 320, February 14, 1876 ; hit, 37° 

 17' S., long. 53° 52' W. ; depth, 600 fathoms; bottom temperature, 2 C, 7 C. ; bottom, 

 hard ground. 



Ascidia translucida, Herdman (PI. XXXIII. figs. 1-6). 



Ascidia translucida, Herdman, Prelim. Rep., Proc. Roy. Soc. Edin., 1879-80, p. 466. 



External Appearance. — The body is ellipsoidal, oblong-ovate, or oblong in shape, 

 and is not flattened laterally; both ends are rounded. It is attached slightly by the left 

 side near the posterior end. The apertures are sessile, and are both on the right side, — 

 the branchial is nearly terminal and median, while the atrial is more than a third of the 

 way down, and at a considerable distance from the dgrsal edge. 



The surface is smooth and glossy. The colour is a very light grey, almost transparent, 

 and the vascular ramifications show as white markings over the left side and the margins 

 of the right. 



Length of the body, 2 - 2 cm.; breadth of the body, 1*2 cm. 



The Test is moderately thick and solid, and is transparent. The vascular trunks 

 enter near the centre of the left side ; they are of large size and branch freely ; they are 

 clearly visible externally, except in the centre of the right side. 



T7ie Mantle is thin and membranous. 



The Branchial Sac is longitudinally plicated, and shows externally a well-marked 

 division into pouches. The internal longitudinal bars are strong, and bear rather long 

 curved papillae at the angles of the meshes; there are no intermediate ones. The trans- 

 verse vessels are all of much the same size, and the horizontal membranes are broad. The 





