^^°7j ^^ronis of the Indian Museum. -^gi 



¥. Fibres of skeleton extremely massive, especially to- 

 wards the external surface, skeleton spicules sausage- 

 shaped, sponge incrusting— S/)o«g///« crasswr ^p 

 nov. ' ^* 



Weber says in his original description of 5. decipiens that the 

 gemmule tubules are short and straight, but I do not find this 

 feature to be constant in Indian specimens. In the same gemmule 

 group, nideed, short, straight tubules and long curved ones often 

 occur, and although Potts states that in S. fragilis the tubules are 

 of equal diameter throughout, I cannot regard this character as of 

 specific value by itself, for in all the species of the subgenus as yet 

 recorded from India the outline of the tubules is frequentlv 

 irregular My examples of 5. fragilis differ from the figures of 

 palaearctic specimens m having stouter skeleton spicules some of 

 ious ""'^ l'""'"^^'^ ^° abruptly that they are almost amphistrongy- 



I now see reason to regard my S. crassissima var. bigemmulata 

 • not as a true variety but as a temporary phase of the species I 

 have only found it at the beginning of the cold season, that is to 

 say, at a date at which the typical S. crassissima is still rare and 

 the ver3' numerous amphioxi and comparative looseness of the 

 skeleton m all my specimens point to immaturity. In several other 

 species, notably in 5. carteri, I find that the skeleton is less com- 

 pact at the beginning of the season than it afterwards becomes 

 although I also find that in S. carteri the strengthening of the 

 skeleton, due chiefly to the development of the transverse fibres 

 does not go so far in some ponds as in others in the same neigh- 

 bourhood. Indeed, I feel confident in stating, after examining 

 a large number of examples of this species z;^ situ in different 

 ponds m Calcutta at different times of the year, and on single 

 occasions at Rajshahi and I^ucknow, that the strength of the 

 skeleton is correlated, whether fortuitously or not I cannot as vet 

 say, with the character of the vegetation of the pond : examples 

 from ponds m which Phanerogamic plants are few, have, towards 

 the end of the cold weather, comparatively stout skeletons, where- 

 as those from ponds in which such plants grow luxuriantly are 

 fragile even at this date ; specimens from both are fragile durini the 

 hot weather and the rains-seasons during which few individuals 

 of b. carteri ^r^ found ahve and gemmules are rarely formed 

 Specimens of this species taken at these seasons are, moreover as 

 a rule smooth and rounded on the surface, with the exhalent 

 apertures few, large and very deep. They are of a pale flesh-colour 

 rarely tinged with green in life, and have the peculiar property of 

 turning spirit a dark brown and becoming brown themselves in 

 alcohol, a property I have not seen in specimens taken at other 

 times of the year. Although the majority of '' hot- weather " 

 specimens are of this form, I have, however, taken others of a more 

 typical one even at this season. 



Ephydatia indica also shows seasonal variation as regards its 



