THE GRAPSOID CRABS OF AMERICA. 106 



San Diego; from Pachydesma crasgatelloidcs ; H. Hemphill; 1 

 female ovig. (2272). 

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



FABIA BYSSOMIAE (Say). 



Plate 24, tigs. 6 imd 8. 



Pinnotheres byssomiae Say, Proc, Acad. Nat. Scl, Philadelphia, vol. 1, 1818, 

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

 coast of United States] ; tj^pe in Mus. Phila. Acad. Sci.). 



Diagnosis. — Legs of second pair unlike, right much longei- than 

 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 maxilliped of subequal 

 size; dactyl 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. 

 Fio. 56.— pabia dyssomiae, odter 4; second leg on right side very much 

 M,vxiLLiPEi) OF FEMALE (25G48), (half agaiu) lougcr than on left side; 



propodites 3 and 4 and left 2 increase in 

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

 po.sterior 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 AscidiaJ*^ 

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



