642 The American Naturalist. [July, 
cavities from two to five inches in depth, and with the diameter from 
one and a half to twice the length of the animal. 
The places selected for these nests are in the bed of the stream, where 
the current is quite swift and the bottom is covered with gravel. 
During the spawning time from one to six have been seen in the 
same nest. In the ordinary season they may be found spawning 
between the middle of April and the middle of May (May 8, 1886, at 
Ithaca, N. Y. ; April 20, 1889, Cedar Rapids, Iowa). 
The length of all the specimens I have examined from New York 
and Iowa is between five and six and a-(}uarter inches.— S. E. Meek, 
Coe College, Cedar Rapids, louia, May 22, i88p. 
Zoological News. — Development of Millepora. — Mr. S. J. 
Hickson, on his recent trip to the Celebes, had an opportunity to study 
the development of the coral Millepora plicata. His account will be 
found in the Philosophical Transactions, Vol. 179 B. This species is 
hermaphrodite. The eggs and spermatozoa arise in the ectoderm, but 
before maturity they break through the supporting layer and enter the 
entoderm. The spermatozoa wander into the dactylozoids and there 
form sperm sacks. The eggs, after a peculiar history, form two polar 
globules, after which they are fertilized. The nucleus now divides into 
numerous portions, each of which becomes surrounded by a mass of 
protoplasm, giving rise to a morula. The next stage is the formation 
of a solid blastosphere, followed by the development of cilia. In some 
cases there was an appearance like the beginning of invagination. Ten 
ciliated embryos escaped through the mouth of the gastrozoids. 
Rotifera.— E. F. Weber, under the title of " Notes on some Roti- 
fers," has communicated to \\i& Archives de Biologic, Sept. 1888, an 
extensive description of the anatomy of some species of these short- 
lived creatures, and of the male and female characters. 
£chinodermata. — H. Bury {Quart. Journal Micros. Soc, Apr. 
1889), puts on record a number of facts in the embryology of that 
stage of the echinoderm larva which has been named the Dipleurula, 
with special reference to the development of the enteroccels and hy- 
drocoels in the different orders. From his observations it appears that 
the Ophiurid Dipleurula develops two pairs of enteroccels metameri- 
cally arranged, and that the hydroccel is formed later, evidently from 
the posterior enteroccel. The echinid larva develops two pairs of 
enteroccels and a waterpore as in the ophiceran, but the hydroccel 
it. In the Asterid Dipleurula anterior and posterior enteroccels may 
