no. uso. SCHIZOPOD CRUSTACEANS— ORTMANN. 27 



rations on right side, and with 10 on the left; and, further, there is a 

 similar serration on the inner margin, just above the upper end of the 

 lamellar part, and opposite to the second tooth (counted from the tip) 

 of the outer margin. 



(3) Lateral wings of carapace produced posteriorly into a long spine 

 on each side, which is almost one-third as long as the carapace (exclud- 

 ing rostrum). 



(4) Sixth abdominal segment with a subdorsal spine directed straight 

 backward on posterior margin, at the base of the telson, on each side. 



(5) Telson slightly more elongated than in L. typicus, and with five 

 marginal spines on each side. The terminal spines are similar to those 

 of L. typicus: two pairs, and between them at the posterior termina- 

 tion a serrated crest, which, however, has only four teeth. (The tip 

 of the telson is not very well preserved in the type, as the two outer, 

 smaller terminal spines are broken off.) 



Measurements. — Total length: 39 mm.; length of rostrum (in front of 

 eyes): 8; length of carapace along dorsal line, including rostrum: 19. 



GENUS GNATHOPHAUSIA Willemoes-Suhm. 



KEY TO THE SPECIES OF GNATHOPHAUSIA: 



a. Antennal scaie small, not jointed, no strong rib terminating in a spine on outer 

 margin; outer margin serrate. Epimera of sixth abdominal segment united ven- 

 trally, forming together a cordiform, concave plate, incised at apex. Dorsal keel 

 of carapace interrupted. Lower lateral keel not curving upward behind, but 

 terminating in a spine at the postero-inferior angle. Branchiostegal lobe gen- 

 erally with a well-developed spine (sometimes obsolete). Maxillipeds with a 

 small exopodite. 

 b. Both lappets of the epimera of the second to fifth abdominal segment pointed 

 and spiniform. Antennal scale subovate, apex shortly pointed. 

 c. Rostrum and all spines of carapace comparatively short or obsolete..,. ingens 

 c / . Rostrum and spines of carapace well developed and comparatively 



long calcarata ( a ) 



V '. Anterior lappet of the epimera of the first to the fifth abdominal segment 



small, rounded; posterior lappet pointed and spiniform. Antennal scale 



sublanceolate, tapering to a sharp, spiniform point.. gigas {-^-drepanephora?) 



a f . Antennal scale large, of usual form, jointed at the extremity, outer margin formed 



by a strong rib terminating in a spine. Epimera of sixth abdominal segment 



not confluent ventrally. 



b. Lower lateral keel of carapace not curving up behind, but terminating in a 



spine on the postero-inferior angle of the carapace. Median keel of carapace 



interrupted, with spiniform serrations. Median line of abdominal segments 



with strong spines. Upper lateral keel of carapace wanting. Two epimeral 



spines on each side of the anterior section of sixth abdominal segment 



Maxillipeds with exopodite gracilis 



¥ . Lower lateral keel of carapace curving up behind; no spine at postero-inferior 

 angle of carapace. Median keel of carapace not interrupted, without spini- 

 form serrations. Median line of abdominal segments — if armed at all — only 

 with posteriorly projecting, small spines. Upper lateral keel of carapace 

 present, very rarely wanting. Maxillipeds without exopodite. 



a G. calcarata may be the young stage of G. ingens. 



