500 Heterogenetic Development in Diaptomus. (May, 
The teeth of this species differ from those of “ Coronatus” too 
much to confuse the two. This species is of the mavus and 
parcus group, but the caudal stylets closely resemble tenuicornis. 
Near Paducah, Ky. 
CYCLOPS MODESTUS, Sp. nov 
Antenne remaining 16-jointed in all individuals seen, very short, 
— o — v —oguvvou vu uY —u; antennules short jointed; fifth foot threejointed, 
with unequal spines; caudal stylets of moderate length, lateral setæ about half way — 
to base of stylet, three longest terminal setze subequal. 
This is a small species related to the preceding, but differs in 
many respects, the form of the spermathzeca is oval. The egg 
sacs are slender, elongate oval. Cullman county, Ala. | 
PoST-EMBRYONAL DEVELOPMENT OF TWO SPECIES OF DAPHNIA. 
In a previous paper it was shown that the spine found on the — 
posterior portion of the shell in young and male individuals, t : 
all members of this genus, is a persisting embryonal characte, ; 
and its possible advantage to the economy of the animal wa — 
pointed out. It was indicated that a recognition of the facts 7 
brought out, would throw several species into synonymy. Pr 
my wish, in this paper, to illustrate the extent of the variations | 
passed through in the course of later development, by two << d 
‘ples, one of which has been but imperfectly described, while te 
other is new to America. pi 
These two species differ from any known to me, though Pa 
may possibly be found among some of Sars’ numerous sii 
species. 7 
DAPHNIA LONGISPINA Herrick (Microscopic Entomostraca, : 77) 
n a figurë 
This name was applied to the young, and in connection à. the 
was given of a male with the spine on the head which, m * 
female at least, was indicative of immaturity. The nae © $ 
particularly appropriate, for the mature female is not €v! 
spined. ; 
This name has been long applied to another form 1 
but apparently to an immature stage of another spede | 
it is really vacant. in a 
In a paper (Notes on Cladocera of Minnesota) if ae 
Geol. Surv. of Minn. 1881, the post-imago is figured, m oW 
of the younger stage (a little distorted in the molt). angel : 
able to complete the chain from the embryo to the posame 
% 
