96 Mr. H. J. Carter on the Freshwater Sponges of Bombay. 



comes based on a mass of them, the lowermost of which merely 

 consist of the refuse of those which have fulfilled the purpose for 

 which they were originally destined*. 



Connected with the growth of Spongilla is also the following 

 fact, which presented itself to me and which is interesting, inas- 

 much as it seems to point out, that germs or full-developed cells 

 of it abound in the water of the tanks, independently of those 

 which exist imbedded in their natural structure : viz. one day I 

 observed a few fresh straws floating together on the surface of 

 the water of a tank which abounded with several species of Spon- 

 gilla ; they had been accidentally thrown there, but before they 

 began to change colour from putrescence, and therefore but a 

 few days after they had been in the water, a growth of Spongilla 

 alba took place around each straw separately, which soon in- 

 creased to the thickness of half an inch. I do not remember to 

 have seen another instance of such rapid growth, and the fresh- 

 ness of the straw proved this rapidity, for in this country it 

 changes colour after a very few days' immersion. 



Although I was perfectly aware that Spongilla might be unco- 

 vered by water for many months in the year and still retain its 

 vitality, yet I wished to see if this would be the case after the 

 interval of more than a year. I therefore placed some portions, 

 which I had kept for this purpose, in tanks supported on bits 

 of cork, and others on stones from which they had been unde- 

 tached ; but from some cause or other, whether from the partial 

 putrescence which its dry fleshy substance subsequently under- 

 went, or from this being present in a larger quantity in sponges 

 taken out of the water in their living state and carefully pre- 

 served, than in those exposed to the sun and winds on the dry 

 rocks throughout the greater part of the year, or from both com- 

 bined, the shrimps and crabs were attracted towards the former 

 and devoured them with rapacity, while they left the latter un- 

 touched ; so that I was at last compelled to enclose a portion in a 

 gauze-wire case, which was kept 3 or 4 feet beneath the sur- 

 face of the water for several months. This portion was fixed on a 

 stone, in the position in which it had grown, and when the case 

 was taken up it was found to have exceeded by many times its ori- 

 ginal bulk, was covered with its natural pellicle, and in the active 

 performance of all its vital functions. 



Colour. — This in all, excepting cinerea, appears to be yellow* 



* Dutrochet has noticed the fact, that in a piece of Spongilla which he 

 kept in water for some months, and which contained seed-like bodies, all 

 the soft parts died, became putrid, and dissolved away during the winter* 

 and that in the following spring the fleshy substance became renewed. — 

 MSmoires pour servir a l'Hisit, Anat. et Physiol, des Vege'taux et des Ani- 

 maux, t. ii. p. 436. 



