No. 10 garth: brachyuran fauna of the galapagos 401 



Stenocionops triangulata (Rathbun) 

 Plate 67, Figs. 1, 2 ; Plate 68, Fig. 2 



Pericera triangulata Rathbun, Proc. U.S. Nat. Mus., vol. 15, p. 246, pi. 



32, fig. 1, 1892. 

 Stenocionops triangulata Rathbun, Proc. U.S. Nat. Mus., vol. 21, p. 577, 

 1898 ; Bull. 129, U.S. Nat. Mus., p. 461, pi. 165, fig. 1 ; pi. 266, fig. 

 1, 1925. 

 Type locality. — Gulf of California, 29 fms. 

 Tj;^e.— USNM No. 16066. 



Range. — West coast of Lower California, Gulf of California (Alba- 

 tross); Bay of Panama (Albatross); 13-51 fms. 



Diagnosis. — From young specimens: nine median spines and a he- 

 patic spine; 3 marginal spines; rostrum one-sixth carapace length, horns 

 strongly divergent. 



Material exajnined (8 specimens from 6 stations). — 

 143-34. Wenman Island, 100-150 fms, Jan. 11, 1934, 1 large male 



(photographed, pi. 67). 

 170-34. East of Wreck Bay, Chatham Island, 32 fms, Jan. 21, 1934, 



1 young male (photographed, pi. 68). 

 317-35. Off Gordon Rocks, Indefatigable Island, 25-30 fms, Dec. 8, 



1934, 1 female. 

 328-35. Tagus Cove, Albemarle Island, 14 fms, Dec. 10, 1934, 1 male. 

 355-35. Gardner Island, Hood Island, 12 fms, Dec. 17, 1934, 2 



specimens. 

 356-35. Gardner Bay, Hood Island, 12-15 fms, Dec. 17, 1934, 2 

 males. 

 Measurements. — Largest male: length 40.0 mm, width 32.9 mm, 

 width between preorbital spines 14.8 mm, cheliped 33.5 mm, chela 14.9 

 mm, rostrum 5.2 mm. 



Habitat. — Sand and coral, coral and nullipore. 

 Depth.— \2-\50 fms. 



Remarks. — From the standpoint of previous records, the reasonable 

 expectation was that Stenocionops ovata (Bell) would be found, since its 

 type locality is Galapagos Islands. However, the smaller specimens all fit 

 the description of S. triangulata (Rathbun) much better. The measured 

 specimen from Wenman Island, of moderately large size, differs from 

 the young in ways characteristic for the members of the genus. Sufficient 

 difference between it and mainland S. triangulata of like size has been 

 noted to suggest the possibility that it may be the adolescent S. ovata, 

 which is known only from the description and figure of a young specimen. 



