ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 307 



in such localities. By this means light may possibly be thrown upon 

 the problem of their possible derivation from the marine sponges. 



Great pleasure and profit may be attained in the same direction by 

 germinating the statoblasts or gemmules under artificial conditions, and 

 studying the development of the young sponges by the aid of as high 

 powers of the Microscope as the ingenuity of each student may bring to 

 bear upon the subject. He further recommends Mr. Carter's directions * 

 for germinating statoblasts, which he considers will be found valuable. 



" To obtain the young Spongillae it is only necessary to get a portion 

 of an old living specimen bearing statoblasts, and, having taken out a few 

 (six to twelve) of the latter, to roll them gently between the folds of a 

 towel to free them from all extra material as much as possible, place 

 them in a watch-glass so as not to touch each other, with a little water, 

 in a saucer or small dish filled with shot to keep the saucer upright 

 and, covering them with a glass shade, transfer the whole to a window- 

 bench opposite to the light. In a few days the young Spongilla may be 

 observed (from its white colour) issuing from the statoblast and glueing 

 the latter as well as itself to the watch-glass, when it will be ready for 

 transfer to the field of the Microscope for examination, care being taken 

 that it is never uncovered by the water, which may be replenished as 

 often as necessary ; but of course the object-glass (when 1/4 in. with 

 high ocular is used for viewing the minute structure) must admit of 

 being dipped into the water without suffusion of the lens." 



His own first experience in the propagation of fresh-water sponges 

 may prove instructive in various ways. Late in the autumn of the year 

 1879, in a pond within the Centennial Grounds, Philadelphia, he found 

 for the first time a living sponge. It was a vigorous, branching speci- 

 men of Spongilla lacustris, charged with gemmules in all parts of its 

 structure. A fragment firmly attached to a stone was taken home and 

 placed in a gallon " specie-jar " with water, in the hope, begotten of 

 inexperience, that it would continue to grow, exhibit its inflowing and 

 exhalent currents, &c. On the contrary, almost necessarily, it died, and 

 in a few days the water became insupportably foul. It was changed and 

 another trial made, which resulted as before. This time the jar was 

 thoroughly cleansed ; the stone with the attached sponge was taken out 

 and held long under the flowing hydrant before it was replaced in the 

 jar, which was now loft in an outer shed and, very naturally, forgotten. 

 Weeks passed and winter came on, and one severe night the water in 

 the jar was frozen solid and the vessel fractured. He supposed that 

 the low temperature to which it had been subjected would prove fatal 

 to the germs, but, as the specimen was a fine one, it seemed well to save 

 it, even in its skeletonized condition. So when its icy envelope had 

 been melted off, the sponge was again thoroughly washed until all 

 the sarcode was removed, when in a fresh jar, it again became a " parlour 

 specimen." 



The author does not clearly remember when signs of germination 

 were first observed. It was probably in January, as during that month 

 artificial conditions very frequently bring about the hatching of such 

 animal germs as those of the polyzoa, &c. He detected first a filmy, 

 greyish-white growth, that seemed associated with the detached gemmules 

 which lay in a groove around the bottom of the jar. A grey, feature- 



* Ann. and Mag. Nat, Hist., 1882, p. 365. 



