CATALOGUE OF TUNICATA. 41 



siphons are much more prominent (PL Cyn. XIV., fig. 2) than in others, 

 and the curvature of the body, and the direction in which the atrial 

 siphon projects, are liable to considerable variation (see figs. 1 and 2). 



The mantle and branchial sac are in all cases of a very dark brown 

 colour, and the internal organs are generally in rather bad condition. The 

 branchial sac is always more or less macerated, and has lost most of its 

 epithelium. In most of the specimens the branchial sac is strongly 

 curved, with the convexity ventral. Both internal bars and trans- 

 verse vessels are of a dark brown colour, so as to form a conspicuous 

 network (fig. 3). 



The dorsal tubercle is inconspicuous (fig. 4), and forms an ovate 

 convex area, upon which a number of small, simple apertures are 

 scattered (fig. 5), very much as in the case of Poly car pa sulcata. In 

 some cases the tubercle is scarcely raised, and forms merely a triangular 

 punctated area. 



The alimentary canal is short and wide, and the anus is crenated 

 round its margin (fig. 6, a.). 



In the largest specimens the tentacles may attain to 45 in number. 

 They are large and stiff, and are in all cases of a dark brown colour, 

 like the lining of the siphons and all the other internal organs. 



The reproductive glands form a large branched organ on the right 

 side, and a smaller on the left, ending in each case in several tubes 

 converging to the base of the atrial siphon (fig. 6, d.). 



Several of the specimens are, like the Boltenias with which they are 

 associated, covered by a thin encrusting soft sponge, like a Halisarca. 



Styela personata, n. sp., PL Cyn. XV., figs. 1 7. 



External appearance. Body short, squat, from globular to quadrate 

 in form, with wide anterior and posterior ends, and compressed laterally. 

 Attached by the posterior end. Apertures at the extremities of the 

 anterior end, distinct but not on long siphons, both 4-lobed. Surface 

 rather corrugated, and in places minutely wrinkled. Colour from light 

 yellow to dark brown. Length 4 cm., breadth 4 - 5 cm., thickness 2 cm. 



Test thin but tough, coriaceous, yellowish on inner surface, and 

 glistening. 



Mantle dark yellow, opaque, not strongly muscular ; adhering to test 

 only at apertures. 



Branchial sac with 4 well-marked folds on each side. There are 

 about 8 to 10 rather wide internal longitudinal bars on the folds and 4 

 visible in the interspace. The meshes are small, elongated transversely, 



