OXYSTOMATOUS AND ALLIED CRABS OF AMERICA §5 



palm longer than fingers, immovable finger triangular, prehensile 

 edge concave; on both fingers finely crenulate, tips overlapping. 

 Chela of minor palm convex above, concave below; fingers carinate, 

 inner edges denticulate, longer than upper margin of palm. Dactyls 

 of first and second ambulatories flattened above, as long as meri. 

 Sternum coarsely granulate. Male abdomen narrow; coalesced 

 segments (3-5) gradually narrowing; sixth segment nearly square, 

 outer margins curved slightly inward; telson triangular, length and 

 breadth subequal, sides arcuate. 



Measurements. — Female, type oi pubescens, total length 26, breadth 

 29 mm. Male (22150), length 13, breadth 14 mm. 



Range.— hower California, Mexico, to Ecuador; 2 to 100 fathoms. 



Material examined. — See table 25, page 86. 



ETHUSA TRUNCATA A. Milne Edwards and Bouvier 



Plate 28, Figures 1, 2 



Ethusa truncata A. Milne Edwards and Bouvier, Bull. Mus. Hist. Nat., Paris, 

 vol. 5, p. 384, 1899 [type locality, Gulf of Mexico (not Antilles), 118-119 

 fathoms; cot3'pes in Paris Mus. and M. C. Z.]; Mem. Mus. Comp. Zool., 

 vol. 27, p. 69, pi. 13, figs. 5-8, 1902. 



Diagnosis. — Eyestalks short and stout, less pigmented above than 

 below\ Sinuses of front shallow. Dactyli of first and second ambu- 

 latories vertically compressed and unusually long, exceeding their 

 respective meri. 



Description. — Carapace longer than wide, slightly but regularly 

 convex from side to side. Cardiac area pitcher-shaped, well de- 

 limited except in front, where it is continuous with the urogastric 

 lobe; behind it there is a small, very prominent, and completely 

 isolated lobe. Mesogastric lobe a plainly marked elevation continued 

 almost to the frontal sinus; behind, in the wide part the limits are 

 indistinct, also the anterior limit of the metagastric lobes which, as 

 customary, are fused with it. The branchial suture is scarcely 

 apparent on the dorsum, the cervical suture is much more visible, 

 especially near the gastric area. Front rather narrow, median sinus 

 very shallow which gives it a truncate aspect. The spinilorm teeth 

 wliicb delimit this sinus are little prominent, somewhat less so than the 

 spines at the external angle of the frontal border; these spines are 

 attached by a straight border to the curve of the upper orbital sinus. 

 They are a little larger than the outer orbital spine, which is not 

 prominent. The next to the last article of the antennal peduncle 

 does not attain the extremity of the spine and the last article sm-- 

 passes it but little. A velvet formed of scattered hairs is always 

 more or less on the carapace. Eyestalks stout, short, surpassing 

 outer orbital spine; their black cornea covers only a part of the upper 

 face but extends all over the lower face. Antennal flagella bare, not 

 reacliing end of chelae. 



