ANCHIALINA OBTUSIFRONS. 197 



17. Anchialina obtusifrons, sp. nov. 

 Plate 2, figs. 4a-4c. 

 Butaritari, Gilbert Islands. Jan. 6, 1900. Lagoon. Surface. Light. 2 adult males. "Albatross." 



Description . — This species is in most particulars closely allied and similar 

 to A. grossa. Frontal plate in the male (fig. 4a) less broad than in A. grossa 

 and produced in a long rostrum reaching slightly beyond the eyes; this rostrum 

 has the lateral margins a little concave, these being proximally somewhat con- 

 verging forward and distally parallel, while the end of the rostrum looks nearly 

 truncate, but its terminal, obtusely triangular portion is in reality bent down- 

 wards and backwards below the apparently terminal part. The eyes are brown 

 and slightly larger than in A. grossa, broader than the end of the stalk which 

 widens considerably from the base outwards. 



Third joint of the antennular peduncle less thick and con.spicuously longer 

 than in A . grossa, being half as long again as broad. Antennal squama about as 

 in A. grossa. 



Gnathopods (fig. 4b) nearly as in A. grossa; second joint very large and 

 much longer than broad; fifth joint strongly expanded, and from the inner side 

 with a very large, lamellar, oblong-triangular, distally blunt process directed 

 inwards and much forwards; sixth joint broad. First jjair of thoracic legs as 

 the following pair, with sixth joint divided into three subjoints. 



Exopod of third male pleopods (fig. 4c) in the main as in A. grossa, with 

 the distal joints much altered and furnished with several processes which 

 constitute a most complex organ, though different in several minor particulars 

 from that in A. grossa. The gigantic lamellar process (a.) on the posterior 

 outer side is much narrowed somewhat before the end and its most distal part 

 is also a little widened; the joint (b.) bearing the terminal processes is much 

 longer than in A. grossa, with a terminal, lamellar expansion covering in front 

 the insertion of these processes (c, d., and e.); finally, the inner process (e.) has 

 more than its distal half very slender, the ramification of the median process 

 (d.) is somewhat different from that in A. grossa, and the very long outer process 

 (c.) has its secondary branch (c. ) adorned with a few low saw-like teeth. 



Uropods with the endopod reaching about the end of the telson and some- 

 what longer than the exopod, which has the end broadly rounded, nearly trun- 

 cate, and 15-17 spines along the outer margin. — Telson nearly as in A. grossa, 

 but the proximal part of the terminal incision is narrower. 



Length 7.5 mm. 



