MUSEUM OF COMPARATIVE ZOOLOGY. Ill 



Dimensions of a male : Total length of carapax, 1.22 ; breadth, exclud- 

 ing the spines, 0.65; length of ambulatory foot of the first pair, 1.30 

 inch. 



It is a more elongated species than any of the three Pisae described by 

 Desbonne and Schramm, which are the only ones as yet indicated as in- 

 habiting the West Indian seas, if, indeed, these species truly belong to 

 the genus. 



The specimens occurred at the following localities and depths : — 



Off Carysfort Eeef, March 31, 1869. Cast No. 1. 52 fathoms, 

 Off Carysfort Reef, March 31, 1869. Cast No. 5. 60 

 Off Alligator Reef, May 8, 1869. Cast No. 10. 118 " 



Pisa praelonga nov. sp. 



Carapax long and narrow, the width across the branchial regions being 

 very little greater than that between the orbits. It is sparsely hairy, and 

 armed with a few very small spines on the sides. Surface beneath the 

 hairs smooth.- Rostrum large, as long as one third the post-frontal length 

 of the carapax; horns slender, acute, divergent. Praeorbital spine slender, 

 acute. Orbit large, with one sharp tooth on the upper margin, near the 

 base of the post- orbital tooth. Basal joint of external antennae with a 

 spine in front (smaller than the pra?orbital spine), and another on the 

 o iter side near the base. 



Dimensions of a male : Length of carapax, rostrum included, 0.39 ; length 

 to the base of horns of rostrum, 0.30 ; breadth, 0.19 inch. 



It differs from all species of the genus hitherto known in the narrowness 

 of the carapax. 



Off Alligator Reef, May 8, 1869. Cast No. 10. 118 fathoms. 

 Off Tennessee Reef, May 7, 1869. Cast No. 7. 124 " 



Milnia bicornuta Stm. 



Pisa bicornuta Latreille, Encyc. Meth., X, 141. 



Pericera bicorna II. Milne-Edwards, Hist. Nat. des Crust., I, 337. 



Pisa bicorna Gibbes, Proc. Am. Assoc. Adv. Sci., 1850, p. 170. 



Pericera bicornis Saussure, Crust. Nouv. du Mexique et des Antilles, p. 12 ; 



pi. i, fig. 3. 

 Milnia bicornuta Stimpsox, Notes on North American Crustacea, p. 52. 



Smith, Trans. Connecticut Acad, of Arts and Sciences, II, 1. 



Found at low-water mark at the Tortugas, and dredged at Key West 

 in 2 to 5 fathoms. 



The generic name Milnia is preoccupied, having been used by Haime 

 for an Echinoid, but it seems scarcely necessary to change it. 



