Boone, Crustacea, Cruises of ''Eagle" and "Ara," 1921-28 183 



Portunus (Achelous) spinicarpus Stimpson. 



Plate 62. 



Diagnostic characters : This crab is readily distinguished from all 

 its American allies by the presence of an extremely long spine at the 

 inner angle of the wrist. In adult males this spine attains a length 

 exceeding that of the palm. 



Type: Founded on a series of specimens taken by the "Blake" at 

 seven stations in the Florida Reefs; i.e., off Tortugas, 13 fms., off 

 Carysfort Reef, 40 fms., off Conch Reef, 49 fms., off Alligator Reef, 

 53 fms., off Pacific Reef, 60 fms., Lat. 31° 31', Long. 79° 41', 74 fms., 

 and off American Shoal, 53 fms., and deposited in the Museum of 

 Comparative Zoology. 



Distribution : Known from Cape Hatteras, N. C, southward in the 

 course of the Gulf Stream through the West Indies to Trinidad, and 

 also at Sabanilla, Colombia, in depths ranging from 3 to 150 fms. 



Color : Unknown. 



Material examined: Port Antonio, Jamaica, February 17, 1928, 

 one male ; three males taken 14 miles S. W. of Marquesas Keys, Flor- 

 ida, dredge down 30 fms., March, 1924 ; one young specimen taken in 

 five fathoms, American Shoal Light, Florida, March 3, 1924; one 

 young male taken at Roncador Bank, Caribbean Sea, January, 1928, 

 by the "Ara," William K. Vanderbilt, commanding. 



Technical description: Carapace oval, produced at the lateral 

 angle into an acute outward-pointing spine which is about one-fourth 

 as long as the width of the carapace between the base of the spines. 

 Dorsal surface convex, decidedly uneven, there is a transverse arcuate 

 line of beaded granules on the mesogastric region, a shorter line be- 

 hind this and subparallel to it; a long curved ridge of beaded gran- 

 ules running in from the base of the lateral spine to the ends of the 

 deep urogastric line and bordered anteriorly by a groove. Two rounded 

 prominences on the cardiac region composed of rounded granules. 

 The entire dorsal surface is finely pubescent. The frontal margin is 

 slightly arched and is armed with six triangulate teeth, including the 

 postorbital pair. The submedian pair are separated by a wide 

 U-shaped sinus but are nearer to each other than they are to the sub- 

 median pair of teeth from which they are separated by an even wider 

 U-shaped sinus. The sinus between the submedian and preorbital 



