THE GBAP801D CRABS OF AMERICA. 105 



San Diego; from Pachydesma crassatelloides ; H. Hemphili; 1 

 female ovig. (2272). 

 San Diego; H. Hemphili; 1 female (17299). 



FABIA BYSSOMIAE (Say). 



Plate 24, figs. 6 and 8. 



Pinnotheres bynsomiae SAY, Proc. Acad. Nat. Sci. Philadelphia, vol. 1, 1818, 

 p. 451 (type-locality, inhabits the Byssomia distorta [southern Atlantic 

 coast of United States] ; type in Mus. Phila. Acad. Sci.). 



Diagnosis. Legs of second pair unlike, right much Ion-:- > t!> ,-u. 

 left. Chelipeds feeble, palm widest at distal end. Legs very slender. 

 Description of female. Of small size. Longitudinal sulci limiting 

 frontal region very deep, parallel for greater part of their length, 

 convergent anteriorly and posteriorly where they terminate in 2 large 

 pits. Posterior margin transverse. 



First and second segments of palp of outer uiaxilliped of subequai 

 size; dactj r l attached behind middle of propodus and not reaching 

 its extremity. 



Chelipeds and legs nearly naked. Chelipeds feeble, but stouter 

 than legs; palms widening a little distally, margins nearly straight, 



a row of long hair on inner side of lower 

 surface, and continued to end of finger ; 

 fingers horizontal, shorter than palm, 

 tips crossing, gape very slight, a tooth 

 near base of dactyl. 



Legs slender; relative length, 2. 3. 1. 

 FIG. 56. FABIA BXSSOUIAE, ODTEB 4 5 second leg on right side very much 

 MAxiLMpsn OF FEMALE (25648), (half again) longer than on left side; 



propodites 3 and 4 and left 2 increase in 



width a little toward distal end, their anterior margins convex, 

 posterior about straight; propodite right 2 half again as long as 

 left 2, of uniform width and slightly curved; propodite 1 widest in 

 middle, subchelate, hairy below distal half; other propodites and 

 dactyls with a few scattered hairs below ; dactyli falcate and similar 

 except that of right 2 which is longer and less curved than its mate. 

 Abdomen covering whole lower surface of body. 

 Measurements. Female (25648), length of carapace 5.4, width of 

 same 6.8, length of right leg of second pair about 12, of left leg of 

 same pair about 8 mm. 



Habitat. Say says of the Byssomia with which this crab is com- 

 mensal: "It imbeds itself in the large Alcyonium of the southern 

 coast, and between individuals of a species of aggregating Ascidia." 

 Range. " Southern coast " ; west Florida ; northwest Cuba. 



