TUNICATA. 319 



sand or shell fragments ; surface more or less corrugated. Colour from dull brownish 

 grey to blackish brown; size, 2*3 centims. x T3 centims. x 0'5 centim. 



Test leathery, but rather soft ; dark grey in the interior, and pigmented with 

 minute black spots to varying degrees having numerous pigmented vessels (fig. 2). 



Mantle moderately thick, but not very muscular, of a dark colour (fig. 3) and 

 having the gonads embedded in it ; apertures and siphons black. 



Branchial Sac nearly black in colour, with four large closely placed folds on each 

 side ; six internal bars on a fold, and three in each interspace (fig. 6). 



Dorsal Lamina a narrow plain membrane. 



Tentacles about 30, all of same size. 



Dorsal Tubercle an indefinite spongy mass with many small apertures (fig. 5). 



Alimentary Canal small, intestine slight. 



Gonads, 10 to 12 round polycarps, sunk in the mantle on each side. 



Localities: (1) Station IV., off Karkopani, 6 to 9 fathoms, one specimen; (2) 

 Station XLVL, off Mount Lavinia, 30 fathoms, one specimen; (3) Gulf of Manaar, 

 three specimens adhering in a clump. 



It is possible that these Ceylon specimens of this widely distributed and somewhat 

 variable species ought to be separated off as a distinct variety. As they have some 

 distinct characteristics, I have drawn up the above description. All the specimens 

 have more brown and black pigmentation than I have seen in the species before, 

 which gives them a "tanned" appearance both inside and out, while the apertures 

 are practically black. In all these characters they agree with HELLER'S Polycarpa 

 nigricans, from Mauritius, which, however, is described as having a basal stalk and 

 root-like processes which are not present in the Ceylon specimen. It is possible that 

 HELLER'S species is the same as QUOY and GAIM ARC'S, in which case aurata remains 

 as the name of the species and nigricans becomes a synonym. 



Polycarpa nmtilans, n. sp. Plate IV., figs. 34 to 44. 



External Appearance. Shape oblong or trapezoidal, with a narrow anterior end 

 and a sloping dorsal edge. Apertures both moderately prominent, but not on long 

 siphons ; branchial anterior and atrial about the middle of the dorsal edge (fig. 38). 

 Surface uneven and corrugated. Colour, dirty greyish yellow ; size, 3 "5 centims. x 

 2 '2 centims. x T5 centims. 



Test tough and leathery, very irregular on outer surface, smooth on inner, white in 

 section. 



Mantle moderately muscular, with fine, but numerous, bundles of fibres running 

 both longitudinally and transversely. 



Branchial Sac, when present, with four folds on each side. The fold has about 

 six internal bars and there are about three in each interspace. The meshes are nearly 

 square and contain each four to six long narrow stigmata (fig. 37). 



Dorsal Lamina a narrow plain membrane (fig. 37). 



