122 University of California Publications in Zoology [Vol. 23 



B. No paired appendages on anterior abdominal segments of either sex. 

 Fourth pair of legs subehelate. 



1. Left cheliped much larger than the right ;. fingers somewhat spooned. 



Dardanus, p. 126. 



2. Left cheliped only slightly larger than the right; fingers acuminate. 



Holopagurus, p. 127. 



II. External maxillipeds widely separated at base. Eight cheliped larger than 

 the left. (As the characters of the following genera are not equally 

 applicable to both sexes, a key including the species of all three is 

 given on page 128.) 



A. A pair of appendages on the first abdominal segment either of male 



only or of female only. Fingers of chelipeds opening and closing 

 obliquely. 



1. A pair of appendages on the first and second abdominal segments 



of the male only. 



Parapagurus, p. 144. 



2. A pair of appendages on the first abdominal segment of the female 



only. 



Pylopagurus, p. 142. 



B. No paired appendages on first or second abdominal segment of either 



sex. Fingers of chelipeds opening and closing horizontally. 



Pagurus, p. 130. 



I. External maxillipeds approximated at the base. Chelipeds equal or subequal, 

 or left larger than the right. ' 



Genus Paguristes Dana 



Chelipeds similar, equal, subequal or one (usually the left) may be larger than 

 the other. Fourth pair of legs simple. External maxillipeds approximated at 

 base. Abdomen with paired appendages other than the uropods on the first two 

 segments in the male, and the first segment of the female. 



Key to the California Species of Paguristes 



I. Eye-stalks moderately stout, two-thirds to three-quarters as long as width of 



anterior portion of carapace. 



A. Upper surface of hands strongly spined with numerous dark-tipped 



spines. Eye-stalks of more or less uniform width throughout their 



entire length. Teeth of front subequal; rostriform tooth reaching 



about to bases of eye scales. 



1. Hands very broad, only about one-fifth longer than wide, outer 



margin strongly convex; immovable finger at base about twice 

 as wide as movable one. (Not known north of San Francisco.) 



bakeri, p. 124. 



2. Hands much narrower, about one-third or more than one-third, longer 



than wide, outer margin but slightly bowed out; immovable finger 

 at base subequal or but slightly wider than movable one. 



turgidus, p. 123. 



