Peo ON HR ESAWATER SPONGES. 
By N. ANNANDALE, D.Sc., F.A.S.B., Superintendent, 
Indian Museum. 
No. XVI.—THE Genus Pectispongilla AND Its ALLIES. 
The genus Pectispongilla was described in 1909 (Rec. Ind. Mus. 
III, p. 103) for the reception of a single species (P. aurea) from 
Travancore in the south-west of the Indian Peninsular Area; the 
subsequent account in the “ Fauna” (Freshwater Sponges, etc., 
p. 106: 1911) added nothing to the generic diagnosis, but included 
the description of another form (subspinosa) from Cochin in the 
same part of India. This form was then regarded as a variety of 
P. aurea. ‘The receipt of fresh material from Cochin has resulted 
in a re-examination of the original specimens and in the detec- 
tion of an error in the generic diagnosis, viz. the statement that 
free microscleres were absent. It has also been found necessary 
to recognize at least three distinct species. 
The genus may now be redefined as follows :— 
Small Spongillinae of massive or encrusting habit, of soft 
and friable consistency, with delicate skeletons in which the 
vertical fibres, though well-defined and not devoid of horny 
substance, are always very slender. Dermal membrane aspi- 
culous. Skeleton-spicules rough or smooth amphioxi; free 
microscleres present in the flesh of the sponge, often of more 
than one type ; gemmule-spicules with the extremities flat- 
tened and expanded in the main axis, the terminal expansions 
bearing, on one face only, large spines arranged longitudinally 
in parallel comb-like rows. 
Type-species.—Pectispongilla aurea, Annandale. 
Geographical Distribution.—The plains of Travancore and 
Cochin in the southern part of the Malabar Zone of Peninsular 
India. 
Affinities.—In the original description of the genus I sug- 
gested that the peculiar gemmule-spicule had been derived from 
that of Ephydatia by a rotation of the terminal rotules. Dr. W. 
Weltner wrote to me shortly afterwards expressing the opinion 
that this type of spicule had more probably been produced from 
one like that of Spongilla by a specialization of the extremi- 
ties. A consideration of the form of the gemmule-spicules in 
the species of Spongilla most nearly related in general structure 
to Pecttspongilla has induced me to accept Dr. Weltner’s views. 
These species of Spongilla constitute a little group in the sub- 
