CUSHMAN: VINEYARD SOUND OSTRACODA. 
363 
jection; antennulae 5-jointed, in the male bearing the sense organ 
at the end of the third joint; sense organ consists of a knob-like thick¬ 
ening at the base bearing many very slender sense hairs; caudal 
laminae with few (5 to 7) ungues. 
Sarsiella americana sp. nov. 
PL 27, fig. 1-6. 
Shell of the female, seen from the side (pi. 27, fig. 1) subovate, 
nearly circular, the infero-posterior angle produced to form a large, 
bluntly pointed, conical process; ventral margin broadly rounded; 
anterior margin slightly sinuous; dorsal margin very irregularly 
notched and bearing two bluntly pointed spines one of which is bifur¬ 
cate at the tip. Seen from the front (pi. 27, fig. 2) the shell is broadly 
truncate at the ventral border and tapers to a blunt point at the dorso- 
posterior angle; central part of the shell broadest, with a blunt pro¬ 
jection at the highest portion. 
Surface of the shell with two elevated ridges nearly at right angles 
to one another, the longest passing from the dorsal margin at the point 
occupied by the two spinose projections to the middle of the ventral 
margin. From this ridge a short ridge passes anteriorly to the margin. 
At the coalescence of these two ridges there is an elevated conical pro¬ 
jection forming the highest point of the surface. The whole central 
part of the shell is raised except at the ventro-posterior angle; the 
upper surface thus formed, is divided by the raised ridges into three 
large depressions, of which the anterior ventral is the smallest and 
the posterior one the largest. The surface has scattered hairs and 
depressions. Anterior and ventral margins closely set with long, 
fairly stiff hairs, with a few scattered ones on the dorsal margin. 
Substance of the shell flexible and submembranaceous; shell when 
dry shriveling and losing its surface characters. 
Height 1.3 mm. Length very slightly greater than the height. 
Antennulae (pi. 27, fig. 3) resemble those of S. capsula and differ 
in having three long setae instead of two on the posterior distal angle 
of the third joint; the last joint with five elongated jointed setae. 
The natatory branch of the antenna (pi. 27, fig. 4) is like that of the 
other species of the genus. The mandible (pi. 27, fig. 5) has a single 
