30 NEW-YORK FAUNA — CRUSTACEA. 



The American Prawn is common on the shores of this State, and is particularly abundant 

 in creeks and grassy bays in the river Hudson. It has been noticed by Say as far south as 

 Florida, and by Dr. Gould along the coast of Massachusetts. It probably ranges still farther 

 north. 



(EXTRA-LIMITAL.) 



P. tenuicornis. (Say, loc. cit. Vol. 1, p. 249.) Rostrum with about eleven or twelve teeth above, 

 and six or seven beneath. Carpus of the first pair of feet unarmed. Fingers of the larger feet 

 as long or rather longer than the palm of the hand. Length, 1 -2. Northern Coast. 



Genus Pen(eus, Fabricius. General form of the preceding. The three first pair of feet didactyle; 



the false abdominal feet terminating in two ciliate plates. Medial caudal plate triangular. 

 P. setiferus. (P. Jluviatilis, Say, loc. cit. Vol. 1, p 236. Edwards, Vol. 2, p. 414.) Rostrum 



serrate above, with about nine teeth above and two beneath. Last abdominal segment and tail cari- 



nate. Color, white tinged with reddish ; abdominal segments greenish yellow spotted with brown; 



caudal plates tipped with green, the cilise red. Length, 7-0 - 8 "0. Abundant on the shores of 



the Carolinas and Florida. 



Genus Mulcion, Latreille. Body soft; thorax ovoid. Eyes concealed. Internal antennae conic, 

 inarticulated and very short ; lateral ones composed of a peduncle and a filament, without dis- 

 tinct articulations, and without a prominent scale at the base. Feet thread-like, and usually 

 with an appendix at their base ; the fourth pair widest. 



M.lesueuri. (Latreille, Griffith's Cuvier, Vol. 13, p. 195, buj; without any details, except that it 

 was collected by M. Bosc in the seas of North America.) 



