16 Memotrs of the Indian Museum. [Vor vale 
Ocean, as the collection contains specimens from no less than six different localities. 
They vary somewhat externally, but in internal structure they agree pretty well 
with Herdman’s original description and figures of this species. The largest speci- 
men, from the Andamans, measures 38 mm. x 2I mm. x 16 mm., and is consider- 
ably larger than those from the Gulf of Manaar. The next largest, also from the 
Andamans, is 26 mm. long and 21 mm. wide. ‘The remaining specimens are all less 
than 20 mm. in length. 
Four of the specimens, from the west coast of the Andamans, have the siphons 
very prominent and the body covered with clear pale yellow sand and small shell 
fragments, and thus look very like the type specimens figured by Herdman (/.c. 
Pl. III, figs. 1, 2, 3, and 4). In another specimen, the largest one, the anterior 
surface of the body is sunk in, undoubtedly in consequence of preservation, and the 
siphons, which are less prominent than in others, are placed at the bottom of this 
concavity. Besides, this specimen is characterized by the well-developed condition 
of the dorsal tubercle which recalls that of Rh. pallida. The rest of the specimens, 
except two mentioned below, have the siphons more or less contracted, but conspicu- 
ous on account of their nakedness. 
The two specimens referred to above are those from East of the Terribles. 
They differ somewhat both externally and in internal structure, and might as well 
be regarded as a distinct variety. The body is nearly globular, and the siphons 
are very short with the apertures scarcely discernible, being thinly covered with 
sand all over. The test is soft, leathery, and transparent. Internally they agree 
in most respects with the typical form, but differ somewhat markedly in the struc- 
ture of the branchial sac. There are seven folds on each side as usual; the internal 
longitudinal bars are, however, much broader and look like so many longitudinal 
membranes, projecting into the lumen of the branchial sac. I counted four to six 
such membranes on a fold and about two in the interspace. The meshes are 
broader than long and contain six or seven stigmata each. 
Microcosmus manaarensis, Herdman. 
(Pl. I, figs. 6 and 7.) 
Microcosmus manaarensis, Herdman, Report on the Pearl Oyster Fisheries of the Gulf of Manaar. 
On the Tunicata, 1906. 
Locality.—Madras coast, 20 fathoms. Twelve specimens. 
I have referred these specimens to this species notwithstanding certain differ- 
ences in the structure of the branchial sac, because they agree quite well in all other 
respects with the original description. They are nearly spherical and form a rough 
mass of sand, foraminifera, and shell fragments, stiff but brittle, with two short 
siphons projecting, and having the posterior end thickly covered and prolonged 
into root-like sandy wisps. The apertures are distant and looking away from each 
other, they are both cross slit. The crust of sand covering the test is 3 to 7 mm. 
thick, and some of the branched root-like processes are more than 20 mm. in length. 
