1912. ] N. ANNANDALE: Sponges of the Malabar Zone. 387 
Indian ally, it is distinguished by the sharp points of its megas- 
cleres as well as by the form of the gemmule-spicules and its 
free gemmules. In external appearance and in the form of its 
megascleres S. gravelyi closely resembles the mountain form of 
Spongilla (Euspongilla) cinerea, Carter, which Mr. Gravely took at 
Medha on the eastern side of the Ghats, but the structure both 
of the skeleton and of the gemmule are completely different. 
Genus CORVOSPONGILLA. 
Annandale, Faun. Brit. Ind., Freshwater Sponges, etc., pp. 
122, 243 (1911); Rec. Ind. Mus., vii, p. 99 (1912). 
When this genus was originally described only two Indian 
species (C. burmanica and C. lapidosa) were assigned to it, but it 
shortly became necessary, owing to the acquisition of fresh 
material, first to describe another Indian species and then to 
transfer to Corvospongilla a fourth species originally referred to 
Stratospongilla. A new race of one of the already-known species 
was also added, and I propose to describe here a new variety of 
another known species. The list of Indian forms now comprises, 
therefore, four species, a subspecies and a variety. 
Owing to these additions to our knowledge of the genus its 
position and characters have become much less obscure, and, 
thanks to specimens recently obtained, a new fact has come to 
light, vzz., that certain forms of the genus produce two kinds of 
gemmules, which differ from one another not only in that one 
kind is fixed to the solid support of the sponge while the other 
lies free in the parenchyma, but also in form, in the structure of 
the external layers and in spiculation. The genus may be 
redescribed as follows :— 
Sponge.—The sponge encrusts rocks or brick-structures in 
the form of a film or a more or less solid layer. It never pos- 
sesses branches or bulky upward projections. ‘There is always a 
stout chitinous membrane at the base 
Skeleton.—The skeleton is always remarkably hard and some- 
times has an almost stony consistency. Except in the basal 
membrane, however, and in the covering of the gemmules, chiti- 
nous substance is often present only in small quantities, although 
in some species it is unusually abundant In some species it is 
difficult to detect a definite skeletal network, while in others the 
skeleton-fibres, and especially the radiating or vertical fibres are 
very stoutly formed. 
Spicules.—The megascleres are never very slender and are 
often stout and amphistrongylous. They are always very numer- 
ous. Flesh-spicules are always present in the form of birotulates 
in which each rotule consists of a ring of very long and slender 
recurved spines. 
The free spicules of the parenchyma have a very characteristic 
form, closely resembling that of the longer gemmule-spicules of 
Heteromeyema and Asteromeyenia. Y.ach has a slender cylindrical 
