KEY TO SPECIES IN THE CAROLINAS 



a. Anterolateral teeth of carapace with margins granu- 

 late ; chelipeds granulate, not denticulate 



irroratua (p. 175). 

 aa. Anterolateral teeth of carapace with denticulate mar- 

 gins ; upper margin of palm denticulate 



borealis (p. 175). 



Cancer irroratus Say. Rock crab 



Figure 155 



Cancer irroratua Say (in part), 1817, p. 59, pi. 4, fig. 2.— 

 Hay and Shore. 1918, p. 435, pi. 35, fig. 1.— Rathbun, 1930a, 

 p. 180, test-fig. 29, pi. 85, fig. 1 (rev.). 



Recognition characters.— Carapace approxi- 

 mately two-thirds as long as wide, convex, granu- 

 lated. Anterolateral border divided into nine 

 teeth with margins granulate, not denticulate as 

 in C. borealis, and with notches between teeth 

 continued on carapace as short, closed fissures 

 giving teeth a pentagonal character. Postero- 

 lateral border a granulated ridge with one tooth 

 at outer end similar to those of anterolateral 

 border but smaller. Front with three teeth, middle 

 one exceeding others and depressed. 



Chelipeds of moderate size, not so long as sec- 

 ond pair of legs; carpus with granulated ridges 

 and a sharp spine at inner distal angle; hand 

 nearly smooth on inner face, outer face with four 

 or five granulated lines, two lower ones continued 

 on slightly deflexed immovable ringer, superior 

 one cristate. Walking legs rather long and slen- 

 der; merus of first and second pairs extending 

 far beyond carapace. Abdomen of male broad, 

 first, second, and third segments with transverse 

 granulated ridge. 



Figure 155.— Cancer irroratus Say. Male in dorsal view, 

 reduced (after Rathbun, 1884). 



Measurements. — Carapace: length, 65 mm.; 

 width, 95 mm. 



Color.— Yellowish closely dotted with dark 

 purplish brown, becoming reddish brown after 

 death. 



Habitat. — Most individuals taken near Beau- 

 fort, N.C., are immature, but larger specimens 

 have been taken farther from the coast. This spe- 

 cies, and the following one, are members of a 

 northern fauna with ranges extending south of 

 the Carolinas only in deep water. Low water mark 

 to 314 fathoms. 



Type locality. — "Inhabits the ocean." [Atlan- 

 tic coast of United States.] 



Known range.— Labrador to South Carolina; 

 shallow water in the North, deeper water in the 

 South. 



Remarks.— This species has a fossil record ex- 

 tending from the Miocene to the present in North 

 America (MacKay, 1943). Ovigerous females are 

 known to occur in March in Florida, and have 

 been reported in August from Massachusetts 

 (Kathbun, 1930a). 



Cancer borealis Stimpson. Jonah crab; northern crab 



Figure 156 



Cancer borealis Stimpson, 1859, p. 50.— Hay and Shore, 1918, 

 p. 434, pi. 35, fig. 2.— Rathbun, 1930a, p. 182, text-fig. 30 (rev.). 



Recognition characters.— Carapace transversely 

 oblong, approximately two-thirds as long as wide, 

 angular at sides, surface granulate. Anterolateral 

 margins divided into nine quadrangular, crenate 

 lobes or teeth, with margins minutely denticulate 

 and with notches between teeth continued on cara- 

 pace as short closed fissures. Front produced 

 beyond internal orbital teeth and provided with 

 three teeth, center one longest and depressed. 

 Orbits circular, with two narrow fissures above 

 and two below ; suborbital lobe strongly produced. 



Chelipeds nearly as long as second pair of legs, 

 stout; carpus and hand with strong, granulose 

 rugae; carpus with sharp spine at inner angle; 

 hand smooth on inner face, heavily rugose on 

 outer face, two rugae continued from hand on 

 slightly deflexed immovable finger; dactyl with 

 rough upper surface, both fingers slaty black at 

 tip. Walking legs short, fringed beneath, dactyls 

 dark tipped. 



Measurements. — Carapace: length, 62 mm.; 

 width, 91 mm. 



MARINE DECAPOD CRUSTACEANS OF THE CAROLINAS 



175 



