266 THE SCHIZOPODA. 



isolated position between the genera with prehensile legs and divided eyes, 

 differing widely from these genera and agreeing with Thysanopoda in having 

 the antennulae similar in both sexes, the endopod of sixth pair of thoracic legs 

 fully developed, five-jointed in both sexes — while in Thysanoessa, Nemato- 

 scelis, and Stylocheiron this endopod is unjointed or two-jointed in the female 

 and wanting in the male — and in the structure and number of i:)rocesses of the 

 copulatory organs; as to the shape of maxillulae and maxillae it is tolerably 

 intermetliate lietween Thysanopoda and NematosceUs. 



Key to the Species. 



a. Frontal ])late obtuse, without rostral process. Eyes dark brownish with a 

 light stripe, di\-ided by a groove and the upper section more than twice as 

 deep as the lower which is very small. Antennular peduncles without 

 any process from the distal outer angle of first joint, and with an at most 

 slightly ]iroduced acute angle above near the distal outer angle of second 

 joint. No dorsal denticles or processes on the abdominal segments. 



N. boopis Calm. 



b. Frontal plate tei'iiiinating in a slender rostrum. Eyes black, conspicuously 

 constricted, with the upper section only somewhat deeper than the lower. 

 Antennular peduncles with a long, spiniform process from the distal outer 

 angle of first joint and with a very conspicuous process from the upper, 

 outer distal end of second joint. Conspicuous dorsal denticles on at least 



two of the abdominal segments. 



a. The process from second antennular joint with at most the proximal 

 half plate-shap ed while the distal part is spiniform. Maxillulae with- 

 out pseudexopod. Third to sixth abdominal segments each with a 

 single dorsal spiniform jirocess from the hind margin, that of third 

 segment generally considerably longer than the others. Distal third 

 of the terminal jarocess of the copulatory organs, seen from behind, 

 tapering to the narrow, obtuse end . . . A^ flexipes Ortm. 



yS. The process from secdud antennular joint is a large, oblong plate 

 slightly acuminate at the acute end. Maxillulae with pseudexopod. 

 Fourth and fifth abdominal segments each with a dorsal row of three 

 sharp teeth from the hind margin, but no denticle on the other seg- 

 ments. Distal thiid of the terminal process of the copulatory organs, 

 seen from behind, very broad with the terminal margin long and incised. 



A^. sexspinosus H. J. H. 



