PHYLLOPODA, CLADOCERA. 
Crust. 40 
Chirocephalus holmani, sp, n., Ryder, P. Ac. Philad. 1879, p. 148, 
TtroodcUt, Woodbury, New Jersey. Cf. also Ann. N. H. (6) iv. pp. 261 & 
252, and J. R. Micr. Soc. ii. p. 876. 
Streptocephalus sealii, sp. n., from Woodbury, New Jersey, and the 5 
other known species of the genus enumerated by Ryder, P. Ac. Philad. 
1879, pp. 200 & 201, with woodcut. 
Artemia salina. A note by C. Briguel, separately published at Nancy, 
has not been seen by the Recorder. 
CLADOCERA. 
A. Weismann describes the spermatozoids and their transmission in 
various genera of Cladocera ; they are immobile in all, and never thread- 
like-elongate, often ovate, or nearly spherical. The size varies between 
0*1 and 00005 mm.; the largest are found in the Polyphemidm Sind 
StididcB. Fecundation is always effected while the eggs are still without 
any envelope ; the spermatozoids are transferred by ejaculation either 
into the oviducts directly {Daphnella, Sida, Latona), the breeding cavity 
of the shell (Bytkotj'cphes), or the ephippium (DaphniincB and Lyn- 
ceidce) ; in the third case many spermatozoids are lost, and therefore their 
number is much larger in these families. The spermatozoids are either 
direct transformations of the cells in the testicle, as in Daphnella and 
Sida^ probably also in the Polyphemidm ; or they are formed within 
other large cells (spermatoblasts), as in Moina, probably also in all 
Daphniinm and Lynceidm. In Scapholeheris, the spermatozoids are very 
minute, and mauy of them are formed within one epithelial cell of the 
testicle ; these dijfferences are in close relation to the number of the 
spermatozoids in each animal. Z. wiss. Zool. xxxiii. pp. 56-110, pis. 
viii.-xiii. 
The author has made numerous experiments upon the times and cir- 
cumstances in which parthenogenetic and sexual generation take place in 
various genera of the Cladocera ; he distinguishes polycyclic^ monocyclic^ 
and acyclic species. In the polycyclic, several sexual generations occur 
in one year, the second from the winter- eggs becoming possibly sexual, 
as in Moina and in other genera which dwell in puddles, pools, and 
marshes easily subject to temporary desiccation. Sida, Daphnia hyalina, 
BythotrepheSy and Leptodora are monocyclic, with only one sexual genera- 
tion a year ; the number of parthenogenetic generations which precede 
the sexual one, is in them respectively about 20, 12, 10, and 6-7 ; they 
live in lakes, the temperature of which is slowly rising and decreasing 
according to the season ; in most of them, the sexual generation is the 
last of the year, but in Daphnia hyalina several parthenogenetic genera- 
tions follow in the autumn. Bosmina^ and in several localities also Chy- 
dorusy are acyclic, only parthenogenetic, without a known sexual genera- 
tion ; they live and propagate during the winter, winter-eggs not being 
necessary for them. In all Cladocera, the first generation of the year is 
parthenogenetic; generally the same female can produce parthenogenetic 
and sexual females ; in Moina, the parthenogenetic female cannot from 
