1917 Waij; on Taaonomy of Crabs 363 



almost as long as propodi. Color grayish white, very much darker after 

 moultings. The carapace measured 1 1 mm. wide and 8 mm. long. 



Found at low tide on Newhall's beach (5) in the mantle of Mya 

 arenaria. 



Family CANCRIDAE 



KEY TO GENERA 



A. Whole margin toothed M'ith serrate edges ; body covered with stiff 

 hairs and bristle-like scales. telmessus (p. 363) 



AA. Posterior lateral margin not toothed ; body not covered with hairs 

 nor bristle-like scales. cancer (p. 364) 



Genus Telmessus 



1, Telmessus cheiragonus (Tilesius) Rathbun. hermit crab (fig. 17) 



Cancer cheiragonus Tilesius ; Telmessus serratus White ; Polycorystes 

 cmbiguus Brandt; Cheiragonus hippocarsinmdes Brandt; Cheiragonus 

 cheiragonus Ortmann. 



Rostrum none, but a deep median depression in the inner antennal 

 front and a smaller notch in the top of each division, making 4 triangular 

 subequal teeth which extend forward about the same distance; long, stout, 

 bristle-like hairs attached to this margin make it somewhat difficult to see 

 these conditions from the dorsal side, but they can be seen clearly from 

 the ventral side. Antennae short. Carapace helmet- or pentagonal- 

 shaped, with a margin of 6 large projecting teeth; the 3 anterior teeth are 

 bordered with 2 tiny spines ; the fourth lateral tooth is very large, pro- 

 jecting out as far again as the other marginal teeth, curving less towards 

 the anterior surface ; the anterior surface of this fourth lateral tooth is 

 roughened by 4 tiny spines, 1 near the point of the tooth and the other 

 3 evenly spaced ones separated from the tiny outer one, the 2 posterior 

 marginal teeth are smaller and have entire margins ; surface of carapace 

 undulated or deeply areolated, covered with broken transverse rows of 

 notched setae-scales and short, stiff, bristle-like hairs ; some of the smaller 

 specimens show no bare areas, but larger ones show small, irregular bare 

 spots on either side of the median line near the center of the carapace, 

 other bare spots are noted anterior to and lateral to these ; posterior lat- 

 eral margin bordered with longer and stiffer hairs than anterior lateral 

 portion. Hands with longitudinal rows of spines on dorsal surface; carpus 

 spiny, hairy, with 1 very large sharp spine on the dorsal side at the dis- 

 tal end ; dactyls darkened for more than half their length, armed with 

 heavy tubercular teeth. Walking legs hairy, scaly, the hairs and scales 

 arranged in transverse rows as on the carapace but farther apart ; hairs 

 on legs longer than on carapace; dactyls slender and longer than the pro- 

 podi, marked with longitudinal grooves, slightly curved at the tip, the 



