XXXII. NOTES ON FRESHWATER SPONGES. 



By N, AnnandaIvE, D.Sc, F.A.S.B., Director, 

 Zoological Survey of India. 



No. XVII.— A NEW RACE OF Trochospongilla latouchiana 



FROM China. 



In my recent account of the freshwater sponges of China I 

 assigned specimens of Trochospongilla from Soochow to T. latou- 

 chiana, mihi, but pointed out that there were differences in the 

 proportions of the gemmule-spicules. Mr. Gee has since sent me 

 a large number of additional specimens, in which the differences 

 are so constant and so marked that I now think they are worthy 

 of nominal distinction. 



Trochospongilla latouchiana subsp. sinensis, nov. 



1918. Trochospongilla latouchiana, Annandale, Mem. As. Soc. Bengal IV, 

 p. 203. 



The sponge appears to have formed small cushions of a 

 greyish colour on sticks or water-plants, but is imperfect in all the 

 specimens examined. The skeleton is compact and contains a 

 considerable amount of horny material by means of which the 

 spicules in the vertical spicule-fibres are fastened together tightly. 

 These fibres are well defined and vary considerably in thickness. 

 As a rule, however, they are not very thick. They ar- connected 

 transversely by an irregular network of single spicules and bundles 

 of spicules joined together at the nodes by horny substance. The 

 sponge is frequently so intermixed with that of Spongilla geei ' 

 that it is impossible to separate the two species, and confusion is 

 liable to occur unless the spicules are carefully sorted out. 



The skeleton spicules are very like those of T. latouchiana * (s.s.) 

 but are rather more slender and more subject to the slight irregu- 

 larities of outHne. They vary considerably in size and proportions 

 but are always quite smooth. The gemmule-spicules are minute. 

 As a rule the outer rotule is slightly smaller than the inner one. 

 The former is rather deeply concave and its margin is very slightly 

 sinuous. The upper end of the shaft is conspicuous as seen from 

 above but the surface of the rotule is not sculptured. The differ- 

 ent rotules do not overlap on the surface of the gemmule. The 

 shafts of these spicules are relatively slender and at least as long as 



' Annandale, op. cit,, p. 202 (1918). 



2 Annandale, Faun. Brit. Ind., Freshiv. Sponges, etc., p. 114, fig. 23A. 



