i4 Memoirs of the Indian M useum. IMOLAVAE 
Cynthia sluiteri, n. sp. 
(PI. fie. 55 pes and 24 
External Appearance.—The body is roundish ovoid in shape, and is not com- 
pressed laterally. The branchial aperture is at the anterior end, and the atrial about 
one-third down the dorsal edge; they are both cross slit, and are borne each on a 
very short, truncated, conical projection. The animal is attached by the ventral edge 
and near the ventral half of the left side. 
The surface in the exposed part of the test is regular and even, but very rough 
from the presence of small pointed scales all over. On the lips of the apertures these 
suddenly increase in size and form large branched spines. The latter, however, are 
not numerous, being arranged in a single irregular row round the aperture. The 
attached surface of the test is provided with numerous short but branched root-like 
processes to which a few shell fragments and sand grains are seen attached. Along 
the boundary line between the free and attached parts of the surface, the test is 
slightly raised, so as to form a very low ridge running in a circle. 
The scales covering the greater part of the test are roundish in outline, slightly 
elevated, and are each provided with a small pointed spine at or near the anterior 
border (Pl. III, fig. 4). The base of this spine is surrounded at some distance by a 
number of much smaller prickles arranged in a circle. The larger spines found on 
the lips of the aperture consist each of a straight stem, tapering towards the tip, from 
which a number of lateral prickles spring at three or four different levels (Pl. III, fig. 3). 
Some of these spines are 1°5 mm. long and are surrounded at the base by a circle 
of curved pointed prickles. There are, besides, smaller spines which look like inter- 
mediate stages between the larger spines and the ordinary scales shown in the figure. 
The colour of the body is a dull greyish-yellow. The tips of the spines and 
prickles are dark brown. The body measures 25 mm. in length and I9 mm. in 
diameter at the broadest part. 
The Test is leathery, not thick (0'5 mm); the inner surface is of nearly the same 
colour as the outside. 
The Mantle is not very thick, but muscular. The musculature consists of two 
layers, an outer layer of fine transverse fibres and an inner layer of much stronger 
longitudinal bands. On the siphons the external fine transverse fibres are wanting ; 
but there is a deeper layer of annular muscle bands which form powerful sphincters | 
at their bases. 
The Tentacles are compound, but not bushy, the branches being rather distant 
and short; they are about twenty in number, five of them being much larger than the 
rest. They are of several sizes and there is no regularity in their arrangement. 
The Branchial Sac has nine broad foids upon each side. There are about 
thirteen to fifteen internal longitudinal bars on the fold, and only three to four in the 
interspace. Every fourth transverse vessel is much wider than the intermediate 
ones, which are all of one size. ‘The meshes are elongated transversely and contain 
each six or seven stigmata. 
