294 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 
from the Ostracoda and used the name Entomosiraca 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 fatlomiat 
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 I1.—Bairdiide. 
Family U1.—Darwinulide. 
Family [V.—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 ccecal 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- 
