Pree we e ig aie aS rig R wa ai, 2 t : Hs A PORN SAR tone t p j 
Wa rr pen A " A i s: 
1886.] Zoölogy. 389 
Dr. C. T. Hudson writes us that “nothing could be more in- 
structive than these curious clusters. In the great majority of 
cases, each rotifer was seen imbedded in a patch of glutinous 
secretion, which was divided from the similar patches of the sur- 
rounding rotifers by sharp straight lines, so as to give the whole 
group the appearance of a tesselated pavement. Here and there 
the Philodines were glued together by long tongues of the same 
secretion; especially were the fibers of the paper projected above 
the general surface, and, by spoiling the level, presented the for- 
mation of a sharp bounding line. In one case, a rotifer had bored 
its way into the fibers of the paper, and, unable to withdraw or 
contract itself, had formed the center of a whole group of others 
attached to it by radiating bands of glue. In fact, these beauti- 
fully clean groups gave ocular demonstration of the truth of Mr. 
Davis’ theory that the Philodines resist drought by encasing 
themselves in a glutinous case of their own secreting, and the 
efficiency of the protective was at once shown by putting the 
strips in water, when the buried rotifers soon struggled into life.” 
— Fourn. Roy. Micr. Soc., February, 1886. 
PARASITE OF THE Rock Oyster.—Mr. W. A. Haskell, on 
€xamining some samples of oysters which were dying in large 
numbers, found that most of them, when opened, presented on the 
inner surface of the shell one or more discolored blisters. In 
some these were of small extent with a narrow sinuous form, 
while in many instances a large part of the valve was affected. 
In some cases, where the extent of the shell invaded was not 
large, the oysters did not seem at all affected by it; in other cases 
€ animal was found to be dead, and in a few cases the shell was 
completely empty. In the interior of the blisters were found one , 
or more specimens of a very small annelid, by which the mischief 
had been effected—Polydora ciliata. One specimen of a secon 
Species was also obtained, P. polybranchia, n. sp., which the author 
describes.— Four. Roy. Micr. Soc., December, 1885. 
_SENSE-orGANs oF Coperop CrusTacea.—Dr. O. E. Imhof has 
Some notes upon the antennary olfactory organs of the genera 
Heterocope and Diaptomus. = 
hese appear to have been discovered in Heterocope by 
Gruber; in Diaptomus they exist in all the species examined,and — 
have a characteristic distribution, which is the same in all the spe- 
ces, and may, perhaps, serve as an additional definition of the _ 
ee 
_ organs of Pontella described by Claus.— Fourn. m> 
