112 BULLETIN OF THE 



Subfamily PERICERINAE. 



Milne-Edwards, Dana, and authors generally, speak of the eyes of 

 Pericera as being non-retractile, having probably studied the genus by 

 means of dried specimens only. In fact, however, the eyes in this group 

 are more perfectly retractile than in any other Crustacea ; so much so 

 that they may be entirely concealed in their orbits, which form a capa- 

 cious cavity with a small, round external orifice. In this cavity the pe- 

 duncle of the eye, the inner half of which is not indurated, becomes bent 

 to a right angle when retracted. 



Pericera trispinosa H. M,-Edw. 

 Pisa trispinosa Latreille, Encyc. Meth., X, 142. 

 Pericera trispinosa H. M.-Edwards, Hist. Nat. des Crust., I, 336 Guerin, 



Iconog. du Regne Anim., Crust., pi. viii, fig. 3. Gibbes, Proc. Am. 



Assoc. Adv. Sci., 1850, p. 172. 



Dredged at Key West in from 2 to 5 fathoms, and found at the Tortugas 

 at low-water mark. 



Pericera camptocera nov. sp. 



Allied to P. trispinosa, but differs as follows : The carapax is narrower 

 and more sparsely pubescent. The four tubercles at the summit of the 

 gastric region are more prominent, forming erect spines. The posterior 

 spine and the lateral spines are longer and more curved. The rostrum is 

 longer, and its horns are regularly divergent from the base. The orbital 

 tubes are more protuberant, and the prasocular and postocular teeth 

 longer. The movable part of the antennae is both longer and stouter. 

 Finally the carpal joint of the ambulatory feet is narrower and not tuber- 

 culated. 



Measurements of a male : Total length of carapax, 0.92 ; length of ros- 

 trum, from base of orbital tubes, 0.25; breadth, between the tips of the 

 lateral spines, 0.70; between the bases of these spines, 0.48 inch. 



One male and one female specimen were taken near Key West in from 

 2 to 5 fathoms. 



Pericera eutheca nov. sp. 



Carapax subtrapezoidal, constricted anteriorly behind the orbits, and 

 broadly rounded behind. Frontal and hepatic regions concave ; gastric, 

 cardiac, intestinal, and branchial regions moderately prominent and each 

 bearing a slender spine. Rostrum very small, forming about one sixth the 

 length of the carapax, nearly horizontal, and consisting of two slender, 

 acute, parallel horns. Orbits very strongly prominent, projecting forward 

 and outward far beyond the antero-lateral margins, forming sheaths longer 

 than the rostrum, and each occupying nearly one third the interorbital 



