THE CANCKOID CRABS OF AMERICA 



233 



partly confluent; the next in size is near the inner angle of the region; 

 behind are 2 very small unequal elevations or tubercles. A well-marked 

 6-parted fan diverges from the posterior margin, the tips of the divi- 

 sions tuberculiform. The antero-lateral area is a smooth concave 

 basin (including the hepatic region). The lateral rim is strongly as- 

 cending, teeth anomalous, oblong, flat, widening from base to ex- 

 tremity, and therefore overlapping; only a slight vestige of a normal 

 midrib is visible in a short ridge terminating in a small incurved 

 spine or spinule; the margin from the first to the eighth tooth is 

 finely and obscurely granulate, from the ninth tooth backward 

 coarsely so. The edge of the inner tooth of the orbit is coarsely gran- 

 ulate, that of the middle tooth of the orbit and of the three teeth 

 of the front have granules of intermediate 

 size. Upper surface of chelipeds rough 

 as in form a, outer surface of palms 

 nearly smooth. Only males of this form 

 or approaching this form have been observed. 



The remarkable variation in form is paralleled 

 in C. am/pJiioetus . 



Color. — Areolae bright red, chelipeds and legs 

 flesh color, fingers black (Walker). Dark red above, 

 lighter beneath; walking legs in some cases with 

 light spots which tend to give the legs a some- 

 what banded appearance. There is considerable 

 variation in color; in some specimens a very irreg- j-jgure 37.— cancer 

 ular band of orange or yellow extends across the oregonensis, male 



, • . ,1_ T -j^l .1 (3076), OUTER MAX- 



carapace anterior to the cardiac groove, with the illiped x4 

 whole carapace more gray and more or less spot- 

 ted ; in others the median line from the posterior end to beyond the 

 cardiac groove shows very gray (Way). 



Measurements. — Female (14964), length of carapace 36.5, width of 

 same 47.1, fronto-orbital width 20.2, width of front between antennae 

 7, width between tips of inner orbital teeth 9.6 mm. 



Range. — From Pribilof Islands and Rat Islands, Alaska, to Santa 

 Barbara, California. 



Material examined. — See table, pages 229-232. 



Family XANTHIDAE 



Canceridae, part (p. 85) -\- Pilumnidae (p. 86) Leach, in Samouelle, The Ento- 

 mologists' Useful Compendium, London, 1819. 

 Xanthidae Alcock, Journ. Asiat. Soc. Bengal, vol. 67, 1898, p. 69. 



Carapace transversely oval or transversely hexagonal or sub- 

 quadrate, rarely subcircular, and almost always broader than 

 long. Front rather broad or very broad, never produced in the 

 form of a rostrum. Antennules folded transversely or obliquely 



