294 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 
from the Ostracoda and used the name Hntomostraca as a group name 
for the Siphonostoma and Lernaeoda. 
Claus used the word Hntomostraca in a different sense. The Phyl- 
lopoda, Ostracoda, Copepoda and Cirripedia were collectively called the 
Entomostraca. 
Professor G. O. Sars has divided the Ostracoda into the following 
four sections: 1. Podocopa, 2. Myodocopa, 3. Cladocopa, 4. Platycopa. 
All of the members of sections 2, 3 and 4 and a portion of those belong- 
ing to section 1 are marine, 
Brady and Norman have divided the Podocopa into the following 
families: 
Family I.—Cypridide. 
Family U.—Bairdiide. 
Family I11.—Darwinulide. 
Family 1V.—Cytheride. 
Family V.—Paradoxostomatide. 
This article treats exclusively of the first and third families. 
FAMILY CYPRIDIDE. 
‘Shell generally thin and horny; valves equal or but slightly une: 
qual in size, surface usually smooth, or simply punctated; ventral 
margins more or less sinuated; hinge margins edentulous. Eyes sim- 
ple, usually confluent, sometimes wanting. Antennules (first anten- 
ne) slender, usually seven-jointed, very flexible, usually provided 
with a number of long hairs forming a dense brush. Antenne (sec- 
ond antenne) pediform, geniculated, four- or five-jointed, clawed at 
the apex, second joint mostly bearing an apical brush of hairs. Man- 
dibles strong, apex strongly toothed, palp four-jointed, with a setifer- 
ous branchial plate at the base. Two pairs of maxille, the first pair 
four digitate; its external branch distinctly two jointed, bearing a 
large setiferous branchial plate; second pair small, composed of a | 
single prehensile lobe and palp, which in the female is generally sim- — 
ple, rarely pediform, is in the male prehensile. Two pairs of feet dis- 
similar in structure, the anterior pair strong, ambulatory, directed | 
downwards, and having a long curved apical claw; posterior bent 
backwards within the shell, and not used for motion. Caudal rami — 
usually well developed, elongated, very mobile, and bearing two or 
three apical claws. Intestine forming two dilations, of which the an- ; 
terior is provided with ececal appendages. Generative organs large, — 
and of complex structure, and partly extended within the valves; in ~ 
the male frequently a whorled sac connected with the testis; copula- 
