332 BULLETIN 129, UNITED STATES NATIONAL MUSEUM 



LISSA BICARINATA Aurivillius 



Plate 73, figs. 3 and 4 



Lissa hicarinata Aurivillius, Kongl. Sv. Vet. Akad. Hand., vol. 23, No. 4, 

 1889, p. 54 (type-locality, St. Barthelemy; type in Stockholm Mus.). — 

 Rathbun, Bull. Lab. Nat. Hist. State Univ. Iowa, vol. 4, 1898, p. 255; 

 Bull. U. S. Fish Comm., vol. 20, for 1900, pt. 2 (1901), p. 64. 



Diagnosis. — Branchial ridge narrow; postero-lateral margin sinu- 

 ous; outer margins of hepatic regions parallel. 



Description. — Carapace with two rounded median prominences, 

 one gastric and one cardiac, the former much larger and higher. 

 From the gastric prominence two ridges run divergently backward 

 to the postero-lateral angles of carapace. Both the median promi- 

 nences and ridges are indistinctly tuberculate. Posterior outline 

 arcuate and separated from the blunt postero-lateral angles by a 

 broad rounded sinus. Sides of branchial and gastric regions steep. 

 Outer margin of branchial region with a broad and shallow tooth at 

 its mxiddle. Outer margins of hepatic regions almost parallel. 

 Rostrum wide, deflexed, subtruncate, widening at extremity, which 

 is four-lobed; median lobes rounded and separated by a narrow 

 U-shaped fissure; outer lobes smaller, blunt, slightly less advanced 

 than median. Upper surface of rostrum slightly concave in a 

 longitudinal direction. There is a short, acuminate preorbital spine 

 directed obliquely upward. Legs furnished with triangular laminate 

 crests. 



Measurements. — Ovigerous female (24120), length of carapace 9.5, 

 width 9.2 mm. Type female (Aurivillius, in letter), length of 

 carapace 7, width 8, length of rostrum 2 mm. 



Range. — Bahama Banks to St. Bartholomew, Leeward Islands; 

 to a depth of 123^2 fathoms. 



Material examined. — 



Bahama Banks; Biol. Exped. State Univ. Iowa, 1893; 1 female 

 (Mus.S.U.L). 



Porto Rico: Mayaguez Harbor; customhouse, NE. f E., 4^ miles; 

 4 to 6 fathoms; Co.; temp. 68° F.; January 20, 1899; station 6065, 

 FisJi Haivk; 1 ovigerous female (24120). 



Off Vieques Island; Point Mula Lighthouse, E. by N., lOf miles; 

 123^ fathoms; Co.; temp. 27° C; February 14, 1899; station 6095, 

 FishHaiol-; 1 female (24121). 



