32 University of California Publications in Zoology [Vol. 23 



Characters. — Carapace and rostrum as long as the first five abdominal seg- 

 ments. The median carina extends backward to the posterior fifth of the carapace, 

 or the cervical groove, and forward along the high, thin rostrum, which reaches 

 half way along the eye-stalks; carina is armed with sixteen small teeth or 

 spines, two of which are on the rostrum and one terminal; below this spine 

 the rostrum is a compressed, finely crenulate lobe. Antennular scale as long as 

 basal joint of peduncle. Antennal scale nearly half as long as carapace proper. 

 First three abdominal segments not carinate; fourth segment posteriorly produced 

 in a thin, compressed spine, which is carinate and has a slight notch at its base, 

 visible in profile; sixth with a longitudinal groove on either side. Telson a little 

 longer than sixth abdominal segment; extremity truncate. 



Dimensions. — Type, ovigerous female: length of carapace and rostrum 23.6 

 mm. ; rostrum 1.8 mm. ; abdomen 42 mm. 



Type Locality. — Off Cortez Bank, California, 984 fathoms ("Albatross" 

 station 2919). 



Remarks.- — This species is akin to P. gilesii Wood-Mason, from the Indian 

 Ocean, which also has a serrated carina running the whole length of the carapace, 

 but the character of the rostrum alone separates it distinctly from that species. 

 In P. gilesii the rostrum is a fine, acute, incurved spine, extending about a third 

 its length beyond the eyes (Eathbun). 



Family Oplophoridae (Hoplophoridae) 



Eostrum moderately or well developed. Mandible with a stout, three-jointed 

 palp, and with incisor and molar process distinct but almost confluent; molar 

 process small. All eight pairs of thoracic appendages with well developed exopo- 

 dites. First two pairs of legs ending in small but well formed chelae; last three 

 pairs of moderate length and subequal. 



Key to the California Genera of the Oplophoridae 



I. Eostrum armed with teeth above and below. Second to sixth abdominal 

 somites, inclusive, sharply carinate. (Known only from 485 + fathoms.) 



Acanthephyra, p. 32. 

 II. Eostrum toothed above only. Abdomen devoid of a median carina. (Know a 

 only from 322 + fathoms.) 



Hymenodora. p. 33. 



Genus Acanthephyra Milne Edwards 



Body compressed. Eostrum rarely short, usually long; armed with teeth 

 above and below. Endopodite of first maxillipeds composed of three segments ; 

 the two inner distal lobes of the second maxilla narrow and projecting beyond 

 the basal lobe. Abdomen more or less carinate; carinae of some segments ending 

 posteriorly in a tooth or spine. Eggs, so far as known, small and numerous. 



