AQA GEOLOGICAL SURVEY OF THE TERRITORIES. 
on already copulated females, with filled uterine bags, which fact agrees 
with what has been observed in Branchipus stagnalis. (In the latter the 
elaspers do not cross.) Slipping off of the female after having once been 
clasped by the male, I could never observe in the normal red Eubran- 
chipus. Therefore comparatively more muscular power is required to 
open the crossed claspers, and owing to this fact only has the copulation 
a longer duration in the pale races; the same difficulty was noticed on 
releasing the copulated female. Immediately after the clasping the post- 
abdomen turns around to the ventral side of the female, the two nor- 
mally crossed cirri-points enter the valvule simultaneously, spreading 
open the same. 
The protruding trifold muscular apparatus, first observed and figured 
by Dr. Heinrich Nitsche, in Branchipus Grubet von Dybowsky (op. cit.), 
is closely brought to the valvule, emptying through it (apparatus) and 
not through the two cirri, the spermatic fluid evidently into the inner 
uterine bag, where it meets with the revolving eggs. The claspers of 
the male tightly pressing upon the anterior (upper) portion of the female 
sack thus produce a gaping of the valvule. All this taking place in 
an instant, the entering of the two cirri, however, is repeated several 
times during the three or four minutes. <A few jerks of the male post- 
abdomen, apparently coincident with strained jerks of the male claspers 
(and following right after) are necessary to free the two sexes. The 
male slowly sinks to the bottom for several seconds, lays curved on its 
back and repeats the post-abdominal jerks with protruded cirri and ap- 
paratus. In this condition, and more so in clay-water, the seminal fluid 
can be observed with an ordinary magnifying glass to ooze out of the 
extensile apparatus and slowly flow over the sides of the curved abdo- 
men. 
II.—LARVAL STAGES OF CHIROCEPHALUS HOLMANI Ryder. 
The single specimen of Chirocephalus found in January, 1880, proved 
to be Chir. holmani Ryder, being consid crap larger, but agreeing in 
general with the latter. On March 2 22, 1881, I found @ very “large ‘and 
deep pond between Glendale and Ridgewood, L. 1., about three miles 
from Maspeth, populated with Chirocephalus holmani. So abundant 
were they that with every 
dip I brought up some 30 to 
50 specimens of both sexes. 
They were of a greenish 
4 transparent hue with their 
furca reddish pigmented. 
The pigment of the furca 
was confluent and not gran- 
ular. 
The males averaged 20™™ 
in length and the females 
Fic. 48.—A, male frontal tentacle of Ch. holmani about 18™™. The stalked 
B, the same in male of Hubranchipus vernalis. eyes were of a beautiful 
dark-red color. Hubranchipus occurred sparingly together with them, 
and now (in May, 1881), also a great number of a variety of (PR CIs 
sanguineus Forbes! and Lymnetis Gouldii Baird. 
Having cbserved them often in copulation in the aquarium, I can 
state that the latter is of very brief duration, and details relate to those 
_ of the normal red Eubranchipas, and principally the frontal tentacles’ 
do not come into play as auxiliary organs. 
The internal genital organs of the male are the same as those figured 
‘Bulletin of Illinois State Labratory of Natural History No. 1. 
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