The greater part of the sponge in this variety consists of a number of compressed but pointed vertical lobes, which arise from a relatively shallow, rounded base, in which the oscula occur. The dried sponge has a yellowish colour. Apparently common in Travancore. * * * * * I cannot distinguish these three "varieties"[AC] from the typical form as distinct species; indeed, their status as varieties is a little doubtful in two cases out of the three. Var. _cava_ appears to be a variety in the strict sense of the word (see p. 18), for it was found on the island of Bombay, the original locality of the species, growing side by side with the typical form. Var. _lobosa_, however, should perhaps be regarded as a subspecies rather than a variety, for I have received specimens from two localities in the extreme south-west of India and have no evidence that the typical form occurs in that part of the country. Evidence, however, is rather scanty as regards the occurrence of freshwater sponges in S. India. Var. _mollis_, again, may be a phase directly due to environment. It is the common form in the ponds of certain parts (_e. g._ in the neighbourhood of the Maidan and at Alipore) of the Calcutta municipal area, but in ponds in other parts (_e. g._ about Belgatchia) of the same area, only the typical form is found. It is possible that the water in the former ponds may be deficient in silica or may possess some other peculiarity that renders the production of spicules difficult for _S. carteri_; but this seems hardly probable, for _S. crassissima_, a species with a rather dense siliceous skeleton, flourishes in the same ponds. I have noticed that in ponds in which the aquatic vegetation is luxuriant and such genera of plants as _Pistia_ and _Limnanthemum_ flourish, there is always a tendency for _S. carteri_ to be softer than in ponds in which the vegetation is mostly cryptogamic, and in Calcutta those parts of the town in which sponges of this species produce most spicules are those in which a slight infiltration of brackish water into the ponds may be suspected; but in the interior of India, in places where the water is absolutely fresh, hard specimens seem to be the rule rather than the exception. [Footnote AC: The only complete European specimen of the species I have seen differs considerably in outward form from any Indian variety, consisting of a flat basal area from which short, cylindrical turret-like branches arise. This specimen is from Lake Balaton in Hungary and was sent me by Prof. von Daday de Dees of Buda-Pesth.]