396 



CRUSTACEA 



anteriorly; length of carapace 8 cm.; width 6.4 cm.: Greenland to Vir- 

 ginia; Europe; North Pacific; in 5 to 1,000 fathoms. 



3. PELIA Bell. Carapace triangular, and much longer than broad; 

 surface smooth; eye stalk in an orbit but not completely concealed: 2 

 American species. 



P. mutica (Gibbes). Small spider crabs. Claw of male with nearly 

 parallel sides and with edges which meet only at the tip: Cape Cod to 

 Florida and the Gulf of Mexico, from low- water mark to 15 fathoms. 



DIVISION 2. CYCLOMETOPA.* 



Carapace more or less circular or elliptical in form and usually 

 broader than long, the front forming a regular arch, and without a 

 distinct rostrum; 9 pairs of gills present: 6 families. 



Key to the families of Cyclometopa here described : 



c t First antennae folded longitudinally or nearly so 1. CANCKIDAE 



3 First antennae folded transversely or obliquely. 



6 t Last pair of legs not flattened for swimming 2. PILUMNIDAE 



6 2 Last pair of legs flattened for swimming 3. POBTUNIDAE 



FAMILY 1. CANCEIDAE. 



Carapace usually broader than long and with very short rostrum 

 or none at all; anterior margin arched and serrate; last pair of legs 

 pointed at the end: about 4 genera. 



CANCER L. Carapace flattened, and more or less elliptical in shape ; 



the outer maxillipeds completely cover 

 the other mouth parts: 11 American 

 species, 2 on the Atlantic coast. 



C. irroratus Say. Rock crab (Fig. 

 630). Anterior margin of carapace 

 with 9 blunt teeth on each side; length 

 of carapace 7 cm.; breadth 10 cm.; 

 color yellowish, thickly spotted with 

 small reddish dots: Labrador to South 

 Carolina; common among rocks and 

 in the sand, in which it may lie buried, 



from low water to 300 fathoms ; the commonest crab on the New England 

 coast, where it is occasionally used for food. 



C. borealis Stimpson. The northern or Jonah crab. Similar to the 

 preceding but larger, with a more convex and much rougher carapace; 

 color brick red : Labrador to Connecticut, often common among the rocks 

 in exposed places, not living under the rocks or in the sandy or muddy 

 bays. 



* See "Synopsis of the Cyclometopous or Cancroid Crabs of North America," by 

 Mary J. Rathbun, Am. Nat., Vol. 34, 1900. 



Fig. 630 Cancer irroratus 

 (Rathbun). 



