126 Records of the Indian Museum. [Vion 4 wilde 
Arachmdium and the new genus may be strictly compared with 
that between these two genera; but the structure of the polypide 
differs from that of any of the Paludicellina and the method of 
budding, although superficially similar, may be distinguished at 
once by the fact that more than one lateral bud is sometimes 
produced on the same side of a zooecium. On the whole, there- 
fore, I am inclined to regard Platypolvzoon as allied to Avach- 
nidium. 
A word may be said about the function of the chitinous 
rods that surround the zooecium in the new species. They appear 
to be capable of being straightened into erect supports, but in 
most of the zooecia in the type specimens are bent in a >-like 
manner, so that the dorsal wall of the zooecium is closely 
approximated to the ventral. This appears to be due to the fact 
that the parietal muscles are strongly contracted and is possibly 
connected with the extrusion of the tentacles of the polypide, 
which in nearly all the zooecia are in a semi-extruded condition. 
No. 2.—ON A NEW GENUS AND SPECIES OF 
MARINE PARASITIC GASTROPOD 
FROM THE INDIAN REGION. 
By HB. PRESTON, ee 25 
E pistethe, gen. nov. 
Shell imperforate, subhyaline, vitrioriform with sunken spire, 
the last whorl overhanging the penultimate. 
Epistethe gonodactyli, sp. nov. 
Shell thin, semi-transparent, sub-covneous, ovate, depressed, 
greyish white above, shading to brownish yellow on the last whorl ; 
whorls 3, rapidly increasing, the first minute, the second over- 
lapped and partly concealed by the last which is, towards the 
latter portion, developed above into a membranaceous infra- 
sutural projection, and is proportionately very large, marked with 
radiate creases and sculptured with microscopic, silky, arcuate, 
transverse striae ; suture impressed in the earlier, cavernous in 
the later stage; base of shell somewhat convex; columella 
callously, outwardly margined, descending in a curve; labrum thin, 
membranaceous, receding below, very slightly projecting in front ; 
aperture depressedly sub-ovate. Alt. 35, diam. max. 6°5, diam. 
min.5 mm. Aperture: alt. 3°5 (nearly), diam. 3°75 mm. 
Habitat.—Parasitic on the ventral surface of a Stomatopod 
crustacean, Gonodactylus chivagra, from shallow water in the 
Persian Gulf; also found on specimens of the same species from the 
Andaman Islands. 
