borders concave, ending in a shoulder separated 

 from acute marginal tooth by an elongate notch 

 at terminus of cervical groove. Antennae slender, 

 smooth, about as long as carapace; basal article 

 strongly produced forward in a spinelike projec- 

 tion; movable articles far removed from orbit. 



Chelipeds strong, heavy, smooth; hand longer 

 than carapace, outer margin fringed with hairs; 

 fingers less than half as long as palm, nearly 

 straight, hooked at tips; length of carpus more 

 than 1.5 times width, a single small spiniform 

 tooth on anterior border; merus with a single 

 broad tooth on lobe at internal angle. First three 

 pairs of walking legs with scattered tufts of 

 hairs ; last pair reduced and carried above others. 



Telson composed of seven elements. 



Measurements. — Male carapace : length, 24 mm., 

 width, 22 mm. 



Color. — Colored with an irregular pattern of 

 reddish longitudinal mottlings on a white back- 

 ground (specimens preserved in alcohol). 



Habitat. — The species occurs near the edge of 

 the Continental Shelf in North Carolina, and is 

 usually found in deeper water than the related 

 and similar species, Porcellana sayana; 27 to 215 

 fathoms. 



Type localities. — Blake Stations: 49, off delta 

 of Mississippi River, 118 fathoms; 36, north of 

 Yucatan, 84 fathoms; 142, Flannegan Passage 

 [V.I.],27 fathoms. 



Known range. — Off Marthas Vineyard, Mass., 

 to northern Gulf of Mexico and southern Gulf of 

 Mexico off Yucatan; West Indies to Virgin Is- 

 lands. 



Remarks. — Ovigerous females have been taken 

 in April, May, June, and November off northwest 

 Florida, Alabama, Mississippi, and Louisiana, 

 and in midwinter off Yucatan. Benedict (1901) 

 was correct in stating that this is the largest 

 porcellanid species in the region. 



Genus Megalobrachium Stimpson, 1858 



Stlmpson, 1858, p. 228.— Haig, 1960, p. 212. 



Megatobrachium soriatum (Say) 

 Figure 89 



Porcellana soriata Say, 1818, p. 456. — Hay and Shore, 1918, 

 p. 404, pi. 29, flg. 6. 



Porcellanopsia soriata: Halg, 1956, p. 35. 



Megalobrachium eoriatum: Haig, 1960, p. 227 (rev.). 



Recognition characters. — Carapace somewhat 

 hexagonal, slightly wider than long; margins 



more or less hairy; areolations well marked, some 

 tuberculate. Front rounded in dorsal view, tri- 

 lobate in frontal view; rostrum little, if any, 

 longer than lateral teeth. Orbits well defined; 

 eyes well developed. Antennae about as long as 

 carapace; basal article strongly produced forward 

 and broadly in contact with margin of carapace; 

 movable articles slender and removed from orbit. 



Chelipeds long and heavy, roughly tuberculate ; 

 hand fringed with long hair along lower margin 

 and with tubercles in rather well-defined rows; 

 fingers with white, strongly hooked tips; carpus 

 with one strong spine and some smaller spines 

 on anterior border, dorsal aspect with tubercles 

 irregularly arranged and appearing granulate 

 under slight magnification; merus ornamented 

 like carpus distally. First three walking legs 

 stout, hairy, and with sharp, curved dactyls; last 

 legs weak and placed above others. 



Telson divided into five elements. 



Measurements. — Carapace: length of male, 5 

 mm., width, 5.5 mm.; ovigerous females, length, 

 4 to 5 mm., width, 4 to 5.5 mm. 



Color. — In life a dirty gray ; in alcohol a rusty 

 or grayish red. 



Habitat. — Free living among corals, rocks, and 

 sponges; in North Carolina found especially in 

 canals of sponges taken from fishing banks off- 

 shore near Beaufort Inlet (Hay and Shore, 1918; 



Figure 89. — Megalobrachium soriatum (Say). Animal in 

 dorsal view, second, third, and fourth legs of left side 

 not shown, 1 mm. indicated. 



112 



FISH AND WILDLIFE SERVICE 



