THE SPIDER CBABS OF AMERICA 247 



California (lat. 32° 17' 00" N.). Depth, from 29 to 1,062 fathoms; 

 seldom less than 250 fathoms. 



Material examined. — See table, pages 248-250. 



CHIONOECETES ANGULATUS Rathbun 



Plates 90 and 91 



Chionoecetes angulatus Rathbun, Proc. U. S. Nat. Mus., vol. 64, art. 14, 

 1924, p. 4 (type-locality, south of Pribilof Islands; 1,401 fathoms; station 

 3604, Albatross; male, holotype. Cat. No. 19303, U.S.N. M.). 



Diagnosis. — Near tanneri. The two dorsal rows of spines and 

 tubercles on the branchial region meet at the outer margin in an 

 acute angle. Interbranchial space not deeply depressed. Rostral 

 teeth as ^vide as, or wider than, the length of their inner margin. 



Description. — Specimens of this species were formerly placed with 

 C tanneri, but the subsequent collection of considerable material 

 demonstrates that the form from northern waters may well be classed 

 as a distinct species. 



Carapace more pubescent than in tanneri; the pubescence of tanneri 

 is less dense and more easily rubbed off. 



Posterior margin of carapace gently arcuate; in tanneri there is a 

 median interruption or small shallow bight. 



Interbranchial space not so deeply depressed; the urogastric region 

 is defined by a groove on either side; in tanneri the whole region is 

 depressed and narrowly compressed. 



The two dorsal ridges on the branchial region converge in straight 

 lines and meet in an acute angle marked by a single, though not simple, 

 large spine ; in tanneri the ridges meet in a curved line marked by two 

 subequal spines. The posterior of these ridges is formed of bunches 

 of acute tubercles, except the outer one or two on each side, which 

 may be spines or spinous ; in tanneri this ridge is composed largely of 

 single spines. 



The rostral teeth are wider, the width at base being in half-grown 

 specimens as great as the length of the inner margin; in old speci- 

 mens, greater than the length. 



Legs more dilated toward the proximal end. 



Measurements. — 'Male, holotype, length of carapace on median line 

 73, width exclusive of spines 78.6, length of first ambulatory leg 182, 

 length of its merus 73.3, greatest width of same merus mthout spines, 

 13 mm. Largest male (46638), length of carapace on median line 



134.4, width exclusive of spines 151.5, length of first ambulatory leg 



356.5, length of its merus 149.7, greatest width of same without spines 

 25 mm. 



Range. — From east coast of Kamchatka (Avacha Bay) eastward 

 through Bering Sea to the Pribilof Islands, thence southward along 

 the Aleutian Islands as far east as long. 167° 25' 00" W. From 



