20 Memoirs of the Indian Museum. [Vor.. VI, 
fig. 6). In one of the specimens the number of internal longitudinal bars on the 
folds and in the interspaces is as follows :— 
End.’8:(7), 09), 5 (14), 7 (9), 9 DE. 
The Dorsal Tubercle is a cordate horse-shoe, with the opening anterior and the 
horns bent inwards at the tip (Pl. III, fig. 8). 
The Dorsal Lamina is very narrow but rather thick, somewhat resembling a 
stout longitudinal bar. 
The Alimentary Canal forms a simple small open loop on the left side of the 
branchial sac. The stomach is distinct, oblong in shape, and longitudinally folded ; 
the intestine is both thin and short for an animal of this size (Pl. III, fig. 7). The 
margin of the anal opening is entire. 
The Gonads are present in the form of numerous elongated polycarps attached 
to the outer surface of the branchial sac. ‘There are about twenty placed along the 
fourth fold on each side, and about fourteen forming a row just below the anterior 
margin of the branchial sac. Each polycarp consists of a central ovarial portion 
surrounded by a peripheral layer of fine testicular follicles (Pl. III, fig. 9). 
Locality.—Madras coast, 20 fathoms. Two specimens. 
The specimens show externally so striking a resemblance to Polycarpa manaar- 
ensis, Herdman, from the Gulf of Manaar, Ceylon, that at the first glance I had 
almost no doubt as to their identity. On cutting them open, however, many points 
of difference in internal structure were found, which necessitated the formation of 
a new species for the present form. Thus, the mantle, which is very thin and 
colourless in our species, is thick, opaque, and ruddy brown in P. manaarensis. The 
dorsal tubercle is a widely open horse-shoe with the horns not turned in in that 
species, whereas it is almost closed in our specimens. The shape of the stomach also 
is not the same in the two species. But perhaps the most important point of differ- 
ence in the internal anatomy is the situation of the polycarps, which in Herdman’s 
species are rounded and embedded in the thick mantle. 
A pair of a macrurous Crustacean was found living as commensals in the 
branchial sac of one of the specimens. 
Monobotryllus violaceus, n. g. and n. sp. 
(PETIT fies. ro-and 115 pl'AWVPties ere) 
External Appearance.—The body of this curious little species is ovoid in outline, 
much depressed, and attached by the whole of the under surface. Along the 
periphery the test is drawn out to form a thin layer with irregularly indented mar- 
* gins. The upper surface is convex and bears the branchial and atrial apertures on 
the longer diameter, placed rather distant from each other. The apertures are both 
simple round holes, not lobed, with somewhat raised lips. The surface is entirely 
naked and smooth and is of a pale greenish-violet colour with a little silky lustre. 
The size of the largest specimen is about 4 mm. in length and 2'5 mm. in breadth. 
The Test is thin, but tough and leathery; on the under surface it is exceedingly 
