566 ^- Annandale, 



of the water or tlie edge of tlie pond wliich are left diy early in 

 the cold weatlier. It is probable that S. homhaijensis resembles these 

 last species in its habits. The manner in which its gemmules are 

 fastened to the solid support of the spong-e must be particularly 

 usefiil in enabling^ them to sprout in a convenient environment as 

 soon as the water reaches them, This is probabl}' the case also as 

 regards S. sumafrana and S. indica, althoiij^h there is some evidence 

 that the latter species flourishes in the cold weather rather than 

 the "rains", and it is noteworthy that in all these three species the 

 skeleton. althougii somewhat compact owing to the large number of 

 spicnles of which it is composed, is incoherent. The fact that the 

 gemnmles remain fixed withont its support, renders it unnecessary 

 for the Kskeleton to persist as a cage containing them (or at any 

 rate a proportion of them) duriiig the period of hibernation or aesti- 

 vation as the case may be. 



Prof. Weber's specimens of S. homhayensis were collected in a 

 river. apparently on stones or rocks, towards the beg-inning- of the 

 S. African summer. They contain comparatively few g-emmules and 

 were evidently in a vigorous condition as regards vegetative growth. 

 Unfortunately we know nothing of the seasonal changes which take 

 place in fresh water sponges in S. Africa. bat the general difference 

 between these changes in Europe and in India shows that they are 

 dependent on the environment as well as the idiosyncrasy of the 

 species. It is very interesting, therefore, to see that the condition 

 of sponges taken in S. Africa differs so widel}^ from that of other 

 individuals of the same species taken in India at the same season. 



In Prof. AVebee's specimens I liave foimd numerous small tnbules 

 €f inorganic debris. These appear to be the work of Chironomid 

 larvae, of which there are several specimens loose in the bottle 

 containing the sponges. Other tubiiles of a very similar appearance 

 but with a delicate chitinoid foundation appear to be the remains 

 of a species of Plmnatclla of which they occasionally contain a stato- 

 blast. The statoblasts are large, elongated and broadly rounded at 

 the ends, the sides being parallel or nearly so. The swim-riug is 

 very narrow, especially at the sides; the following are the measure- 

 ments of one of the statoblasts: Length 0,4128 mm, breadth 0,2064 mm; 

 length of central capsule 0,3268 mm, breadth of central capsuie 

 0,1892 mm. I do not think it possible to identify the species of 

 this genus by means of the statoblast alone, and all that can be 

 Said of the other characters of the form to which this particular 



