COPEPOD GENUS DENTIGRYPS — LEWIS 377 



times unusable because the terminal process of that leg may be broken 

 or lost completely. 



1. Fifth leg not appearing 2-parted, terminal process short; median cephalo- 



thoracic region not completely covering fourth pedigerous segment, if 



covering it at all 2 



Fifth leg appearing 2-parted, terminal process forming the second part; 

 median cephalothoracic region covering the fourth pedigerous segment . . 3 



2. Sternal furca with chisel-shaped tines; fourth thoracic leg with spilcehke 



projection of inner distal surface D. ulua 



Sternal furca with bluntly pointed tines ; fourth thoracic leg without spikelike 

 projection of inner distal surface D. bifurcatus 



3. Terminal process of fifth leg naked; postoral process simple, not bifurcate. 



D. curtus 

 Terminal process of fifth leg plumose; postoral process bifurcate . . . D. litus 



Discussion of the Genus 



In the original description of the genus Dentigryps, based on the 

 female of D. curtus, Wilson (1913) indicated that owing to the 

 similarity of their appendages the genus was allied to Lepeophtheirus, 

 but differed from it in the nature of the free fourth pedigerous segment 

 and genital segment. He also compared the genus with Homoiotes 

 on the basis of the fom^th pedigerous and genital segments which, 

 he noted, were fused and covered "with a plate similar to the carapace." 

 Wilson further compared the genus to the euryphorid genus Gloiopotes 

 on the basis of the fifth legs, to the pandarids on the basis of the 

 "dropping of the abdomen to the ventral surface and its transference 

 forward," and finally to the euryphorid genus Alehion because of 

 posterior lobes found on either side of the caudal rami of the female 

 of D. curtus. With the availabilit}^ of new material that includes 

 several new species and the previously undescribed male of D. curtus, 

 it is possible to reevaluate the genus and its relationships with members 

 of the families Caligidae and Em-yphoridae. 



Members of the genus Dentigryps do indeed possess characteristics 

 in common with members of the families Caligidae and Euryphoridae. 

 But although the general composition of the cephalothorax, except 

 for the euryphorid genus Dysgamus, is similar in both families, the 

 presence of large and distinct fifth-leg projections, especially in the 

 female, allies Dentigryps to the family Euryphoridae, although even 

 in this family there are members without the projection (e.g., the 

 female of Alehion glaher). In euryphorids that do possess it, however, 

 the fifth-leg projection is often more complex than that of members 

 of the genus Dentigryps, a condition that Gloiopotes ornatus exemplifies 

 well, the fifth-leg process in this species being heavily serrated. The 

 presence of some indication of platelike formations of the dorsal 



