Male abdomen with sides gradually convergent, 

 seventh segment not more than 1.5 times as long 

 as wide; female abdomen with sides of triangular 

 portion straight. 



Measurements. — Carapace: female, length, 1.6 

 mm., width, 3.1 mm.; male, length, 2 mm., width, 

 3.5 mm. 



Habitat. — Approximately 3 or 4 to 40 fathoms. 



Type locality. — Off Cape Catoche, Yucatan, 

 [Mexico] ; Albatross station 2362. 



Known range. — Off Charleston, S.C. ; south of 

 Tortugas, Fla.; Puerto Rico; and type locality. 



Remarks. — Ovigerous females have been taken 

 in Florida in August. The ovigerous specimen 

 taken in Puerto Rico (no date) was found among 

 ventral spines of a rose sea urchin (J. A. Rivero, 

 U.S. National Museum). 



Genus Dissodactylus Smith, 1870 



Rathbun, 1918b, p. 114. — Hemming, 1958b, p. 31. 



Dissodactylus mellitae Rathbun 

 Figure 192 



Echinophilis mellitae Rathbun, 1900a, p. 590. 



Dissodactylus mellitae: Rathbun, 1918b, p. 117, text-fig. 66, 

 pi. 28, figs. 7-8 (rev.).— Hay and Shore, 1918, p. 444, pi. 36, 

 fig. 1. 



Recognition characters. — Minute. Carapace 

 about one-fourth wider than long, slightly wider 

 at lateral angles than posteriorly, dorsal surface 

 convex, smooth, and polished except anterior por- 

 tions slightly pubescent. Edge of front concave, 

 fringed with short hairs. Anterolateral borders 

 arcuate, with a fine raised rim curving inward on 

 carapace at lateral angles and continuing medio- 

 posteriorly for some distance; posterior margin 

 sinuous. Orbits opening medially, eyes small. 



Figure 192. — Dissodactylus mellitae Rathbun. 

 dorsal view, 2 mm. indicated. 



Animal in 



Outer maxilliped with fused, spatulate merus and 

 ischium; outer edge of carpus arcuate; propodus 

 quadrate. 



Chelipeds short and stout; hand longer than 

 other articles combined, cylindrical, upper and 

 outer faces bearing a few impressed, short, oblique 

 lines with short appressed hairs extending dis- 

 tally; fingers considerably shorter than palm, 

 bent inward and curved, opposable margins with 

 tufts of short bristles ; carpus with a distal fringe 

 of short hairs and an impressed line similar to 

 those on chelae; merus short and stout, lower sur- 

 face with oblique lines. First, second, and third 

 walking legs stout, margins fringed with short 

 hairs, dactyls deeply bifid; fourth walking legs 

 with sty li form dactyls, fringed with long hairs on 

 margins. 



Abdomen of male with first and second, and 

 third to fifth segments partially fused, margins 

 convex; telson subtriangular with convex sides. 

 Abdomen of female with first segment linear, sec- 

 ond to fourth fused; telson broadly triangular, 

 half as wide as sixth segment, sides sinuous. 



Measurements. — Carapace: male, length, 2.9 

 mm., width, 3.5 mm. ; ovigerous female, length, 

 3.3 mm., width, 4.5 mm. 



Color. — Light, with scanty dark mottlings 

 which persist in alcohol and are then of purplish 

 color (Rathbun, 1018b). 



Habitat. — This species clings to the outside of 

 the keyhole urchin Mellita quinquesperforata and 

 the sand dollars E china rachnius parma and En- 

 cope michelini. The crabs are easily overlooked 

 because as the sand dollars are lifted from the 

 water, the small crabs may move about and drop 

 off. Shallow water to 11.5 fathoms. 



Type locality. — Pensacola, Fla., on Mellita 

 quinquesperfo rata. 



Known range. — Western part of Vineyard 

 Sound, Mass., to Charleston, S.C. ; western Flor- 

 ida. 



Remarks. — Hyman (1924a) described the first 

 zoeal stage of this crab, comparing it to the zoea 

 of Pinnotheres maculatus, and reported it as com- 

 mon in plankton tows in the Beaufort, N.C., area 

 in summer. Ovigerous females occur there during 

 the same period, and are reported front Narragan- 

 sett Bay in August (Rathbun, 1918b), and in 

 Florida from July to October (Wass, 1955, in 

 part). 



MARINE DECAPOD CRUSTACEANS OF THE CAROLINAS 



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