-[]^4 BULLETIN 16G, UNITED STATES NATIONAL MUSEUM 



Material examined. — As follows: 



Puerto Rico: Off Vieques; Ciilebritas lighthouse NE. }{ N., 10 miles; 

 15 fathoms; Co.; February 8, 1899; station 6091, Fish Hawk; 1 female, 

 holotype (23777). 



Barbados: 1 mile southwest of Pelican Island; 38 fathoms; fne. 

 Co. frag.; May 13, 1918; station 1, Barbados-Antigua Expedition, 

 State University of Iowa; 1 female, same size as type (S. U. I.). 



CLYTHROCERUS PLANUS Rathbun 



FiGUUE 29; Plate 34, Figures 1, 2 



Cydodorippe plana Rathbun, Amer. Nat., vol. 34, p. 519, 1900. 



Clythrocerus planus Rathbun, Harriman Alaska Expedition, vol. 10, p. 168, pi. 9, 



fig. 4, 1904 [type locality, southern California at Catalina Harbor (probably); 



type, U.S.N.M. no. 14256]. 



Diagnosis. — Carapace finely and appendages coarsely granulate. 

 Two lateral teeth or spines, the distance between them greater than 

 between the foremost tooth and the orbital tooth. 



Figure 29.— Clythrocerus planus, male: Dorsal view, X12. 



Description. — Carapace subcircular, a little broader than long; 

 dorsally flat, finely granulate, granules larger toward outer margin; 

 gastric and cardiac-intestinal regions bounded by deep grooves. 

 Front occupied by two triangular lobes, each tipped with a blunt 

 tooth, and separated from each other by a broad V-shaped sinus, 

 which is prolonged on the dorsal surface by a broad, shallow depres- 

 sion continued to gastric region; outer margin of each lobe slightly 

 concave. Outer orbital tooth narrow, blunt, well-marked, directed 

 obliquely outward. A tooth a little in front of middle of lateral margin 

 is somewhat larger and directed forward and slightly outward. A 

 much smaller triangular tooth at about one-third the distance from 

 orbital to branchial tooth. Antennules hidden under carapace; 

 antennae moderately enlarged. Anterior end of buccal cavity and 



