54 NEW-YORK FAUNA — CRUSTACEA. 
This singular crustaceous animal is found adhering to rocks in and near the water of West- 
Canada creek. It is detached with considerable difficulty, and when so detached, partially 
rolls itself up. It was thought a singular coincidence, that animals bearing so strong an ex- 
ternal resemblance to trilobites should be found at the most remarkable locality in the United 
States for these extinct animals. It is not supposed that they properly belong to this order, 
to which, they are, however, allied by external form; but the form of the mouth compels us 
to arrange it among the Branchiopodal Crustacea, or Crustacés suceurs of more recent writers. 
I feel much indebted to Mr. I. Cozzens for another species from Rye, Westchester county. 
FLuvicoLa TUBERCULATA. 
(STATE COLLECTION.) 
Description. Body ovate-oblong, sublinear, arched along the medial line. Anterior seg- 
ment rounded in front, terminating in produced points on each side behind ; second and third 
segments larger than the following, which become successively smaller ; the lateral segments 
oblong, quadrangular : the whole disk margined with closely beset hairs as in the preceding. 
On each side of the dorsal ridge, and closely contiguous to it, is a longitudinal series of abbre- 
viated oblong elevations, which, on the three anterior segments, become more elongated, and 
form a depression between them instead of a ridge. Near this series, and parallei to it on 
each side, is a similar series of somewhat oblique tubercles, and a third series more distant, 
and apparently defining the boundaries of the lateral lobes. In desiccated specimens, these 
series of tubercles, crossing the raised edges of the segments, divide the surface into a series 
of quadrangular compartments. In other respects resembling the preceding. Color, reddish 
brown. 
Length, 0°2-0:5. 
Attached to stones in brooks at Rye, Westchester county. 
