34 University of California Publications in Zoology [Vol. 23 



Hymenodora frontalis Eathbun 



Hymcnodora frontalis Eathbun, Proc. IT. S. Nat. Mus., 24, 904, 1902; 

 H. A. E., 10, 28, 1904. 



Fig. 20. Hymenodora frontalis, ?, X about 2 (from Eathbun, U. S. N. M.). 



Characters. — Surface covered with very fine wrinkles or rugose lines. Carapace 

 and rostrum more than half as long as abdomen; median carina advanced in a 

 rostrum which is unusually long for the genus, being from two-fifths to one-half 

 as long as the remainder of the carapace and reaching the end or a little beyond 

 the end of antennular peduncle. Eostrum a slender, sharp-pointed spine, distal 

 half slightly curved upward, basal half armed above with three to six spines, two 

 or three of which are beyond the line of the orbit. Abdomen devoid of a median 

 carina or median spines; sixth segment two and a half times as long as fifth, and 

 between three-fourths and four-fifths as long as telson. 



Dimensions. — Type, male: length of carapace and rostrum 19 mm.; of rostrum 

 6.5 mm.; of abdomen 32.5 mm. 



Type Locality. — West of Unalaska, 322 fathoms ("Albatross" station 3327). 



Distribution. — From Bering Sea to off San Clemente Island, California, and 

 Kamchatka; 322 to 1771 fathoms. 



Bemarks. — The unusually long rostrum distinguishes this from other species 

 of Hymenodora (Eathbun). 



Family Palaemonidae 



Eostrum well developed, laterally compressed, and armed with teeth. Anten- 

 nules with three flagella, owing to cleavage of one almost or quite to the base. 

 Mandibles with incisor process, and with or without palp of three segments. First 

 pair of legs chelate and shorter than second. Second pair equal and chelate, with 

 segmented carpus, chelae generally larger than in first pair. 



