362 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
TRIBE 1. MYODOCOPA. 
The shell is ovate or elongate-ovate, sometimes truncate behind, 
often produced at the infero-posterior angle; the lower side of the 
front margin has usually a sinus for the protrusion of the antennae, 
above which the shell is produced in a more or less rostrate form. 
The valves are calcareous or thin and submembranaceous with the 
surface smooth and polished, hispid, or variously sculptured. 
The antennulae are not adapted for swimming, but usually bear 
the sensory appendages. The antenna has a very large basal joint 
with two branches, one with long plumose setae for swimming, the 
other rudimentary in the female, but in the male fitted for grasping. 
The caudal laminae consist of a pair of plates with numerous ungues 
on the margin, that increase in length toward the end. 
This tribe seems to bear a close relation to the Cladocera and 
especially reminds one of them in the antennal sinus, the caudal 
laminae, and the method of carrying the ova within the hinder part 
of the shell. 
FAMILY CYPRIDINIDAE. 
Shell with a deep incision in front for the protrusion of the antennae 
(except in the female of Sarsiella). Antennulae stout, 5- to 8-jointed, 
the fifth joint in the male bearing the large sense organ; antennae 
with the outer branch usually 9-jointed, inner branch in the male 
3-jointed; mandibular foot 5-jointed, terminating in ungues; fol¬ 
lowing limbs maxilliform; caudal laminae oval or subtriangular, 
with numerous ungues. 
Genus Sarsiella Norman. 
Sarsiella Norman, ’ 68 . p. 293; Sars, ’ 87 , p. 55; Brady, ’ 90 , p. 516; G. W. 
Muller, ’ 94 , p. 213. 
Streptoleberis ? Brady, ’ 90 , p. 515. 
Nematohamma Brady and Norman, ’ 96 , p. 680. 
Shell of female without antennal sinus, latero-posterior angle pro¬ 
duced; shell of male elongated with antennal sinus and rostral pro- 
