1887] Pilar. 485 
Vitality of Encysted Forms.—Nussbaum, while studying 
the phenomena of digestion in Hydra, noticed that in the ex- 
crementa of the polyp there was a living embryo of shih 
the mother of which had just been eaten by the Hy 
nettle-cells which killed the parent had not been able fa affect 
the young. Led this, Nussbaum killed pregnant female 
Daphniæ with absolute alcohol and observed that the embryos 
afterwards developed, proving that the cyst was a great pro- 
tection. This immunity of the Daphnia embryo is, says Nuss- 
baum, of great importance to the perpetuation of both the Hydras 
as well as of the Daphnia itself. With their voracious appetites, 
a few Hydras would rapidly depopulate a pool, and then would 
have to eng themselves were it not for the protection afforded 
the embryos by these resisting cysts. A similar instance is 
afforded oe the seeds of many ‘plants which, as is well known, 
pass uninjured through the alimentary tracts of many fruit-eating 
animals. 
Sense-Organs of Sponges.— Von Lendenfeld describes, under 
the name synocils, some peculiar sense-organs in Grantia which 
had previously been described by Stewart as palpocils. From 
length, most numerous near the incurrent pores. These organs 
SS T $ 
Synocils of Grantia ciliata. After von Lendenfeld. 
consist of prolongations of the mesodermal intercellular sub- 
d are apparently covered with a delicate epithelium. 
At the base are several oval nuclei, each surrounded with an 
irregular envelope of protoplasm, which sends out root-like 
rocesses, one of which runs to the tip of the synocil (see cut). 
