564 N. Annandale, 



spicules — the latter perbaps not a very importance difterence ^ 

 while in S. sumatrana and S. indica there is only one layer of spicules 

 on tlie gemmule. S. navicella Carter, from the Amazons, seems also 

 to be an allied form, but is distingnished by the shape of its gemmule 

 spicules, especially those nearest the gemmule; for the gemmule 

 spicules are stated to differ in accordance with their position as 

 regards the gemmule. A similar difference in the gemmule spicules 

 of different layers was noticed by Carter in S. homhaijensis and is 

 easily detected in some gemmules. In others, however, it is not 

 perceptible, and I believe that it is due to the fact that the outer 

 spicules do not alvvays reach the same perfection of development 

 as those which are formed first and are therefore nearer the 

 gemmule. 



The specimens collected by Prof. Weber in Natal and those 

 collected by myself in the Bombay Presidency were both obtained 

 in the month of November. It is therefore very interesting to 

 compare them from a biological point of view. In so doing it must 

 be remembered that while in S. Africa November is near the 

 beginning of summer, in India it is at the beginning of the "cold 

 weather", that is to say both the coolest and the driest season of 

 the year. The lake in which my specimens were obtained had. at 

 the time when they were collected, already sunk some inches below 

 its highest level, leaving bare a gently sloping bank of small stones. 

 Adhering to the lower surface of these stones I found many small 

 patches of Spongüla bomhayensis, quite dry but complete so far as 

 their harder parts were concerned and with the gemmules fully 

 formed at their base. From the shallow water at the edge of the 

 lake I took many similar stones which still remained submerged. 

 It was evident that the sponge had been just as abundant on their 

 lower surface as on that of the stones which were now dry; but 

 only the gemmules remained, sometimes with a few skeleton spicules 

 adhering to them. The bulk of the skeleton had fallen away and 

 the parenchyma had wholly perished. In a few instances a small 

 sponge, one or two millimetres in diameter, had already been formed 

 among the gemmules; but these young sponges appeared to belong 

 to some other species, possibly SpongiUa indica, which was also 

 common in the lake. 



Carter's^) specimen of S. hombaijensis, which was evidently in 



1) In: Ann. Mag. nat. Hist. (5), Vol. 10, p. 369 (1882). 



