462 
Proceedings of the Royal Society 
Surface smooth but mamillated, very strongly on the anterior half, 
and especially near the branchial aperture where a few more sharply 
cut papillae are visible. Colour light smoky brown, rather deeper in 
tint at the anterior end. Length, 8 cm ; breadth, 4 cm. 
Test cartilaginous, thickish, of a light greyish-brown colour through- 
out. Vascular trunks enter the test on the left side about half- 
way down, and large vessels ramify on the inner surface. 
Mantle moderately muscular. 
Branchial sac plicated longitudinally; the transverse vessels divide 
the grooves into rows of pouches, which are rather irregularly 
placed, and have no relation to the internal longitudinal bars. Trans- 
verse vessels all nearly of one size ; meshes transversely oblong, con- 
taining each eight to ten stigmata; papillae large and irregularly 
shaped, no intermediate smaller ones. 
Dorsal lamina ribbed transversely, and strongly pectinated at the 
margin, a rib running out to the apex of each tooth. 
Tentacles numerous, filiform, sixty-two large ones and about the 
same number of very minute intermediate ones. These last are so 
small as to be easily overlooked ; usually one is placed between each 
pair of large tentacles, but in some spaces there appears to be none. 
Olfactory tubercle large, irregularly oval in outline. 
One specimen, in excellent condition, from Station 162 (Bass’ 
Straits), 38 to 40 fathoms. 
This species agrees in the thickness of its test with the next two 
species, and in the structure of the branchial sac with these and some 
others. The difference of size in the tentacles, the condition of the 
dorsal lamina, the transversely oblong meshes, and the absence of 
intermediate papillae are all important characters. 
Pachychlcena obesa , n. sp. 
External appearance. — Shape unknown, on account of the absence 
of the greater part of the test, probably oval or irregularly spherical. 
Apertures not distant, depressed. Surface smooth, mamillated. 
Colour dark earthy-brown. Length probably about 1 0 cm. ; breadth 
about 6 cm. 
Test cartilaginous, thick (8 mm.), solid, opaque ; vessels visible on 
the internal surface. 
