32 University of California Publications in Zoology [Vou. 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 sixtcen 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 (Rathbun). 
Family OpLOPHORIDAE (HOPLOPHORIDAE) 
Rostrum 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. 
Kry To THE CALIFORNIA GENERA OF THE OPLOPHORIDAE 
I. Rostrum armed with teeth above and below. Second to sixth abdominal 
somites, inclusive, sharply carinate. (Known only from 485 + fathoms.) 
Acanthephyra, p. 32. 
II. Rostrum toothed above only. Abdomen devoid of a median carina. (Known 
only from 322 + fathoms.) 
Hymenodora, p. 33. 
Genus Acanthephyra Milne Edwards 
Body compressed. Rostrum 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. 
