MARINE AMPHIPODA IN MICRONESIA — BARNARD 



499 



a minute notch; no segments with dorsal teeth; telson with rounded 

 apices, no lateral notches, each lobe with a spine about halfway to 

 base; gnathopod 1 unusually stout; gnathopod 2 with oblique palm 

 and microscopic translucent ridge along distal haJf. 



Holotype: USNM 106877, ovigerous female, 3.5 mm. Unique. 



Type locality: Abbott station 23-E-2, Ifaluk Atoll, Sept. 4, 1953. 



Figure 10. — Elasmopus atolgidus, new species, holotype, female, 3.5 mm., Abbott sta. 

 23-E-2: a, head; b, pleon segments 1-3; c, d, gnathopods 1, 2; e-g, pereopods 2, 4, 5; 

 h-j, uropods 1, 2, 3; k, telson. 



Relationship: This single specimen is so unique to the atoll collec- 

 tions that it is worthy of description, despite its slightly damaged 

 condition and the fact that it is a female. The species needs distinc- 

 tion from only two others described, because of the combination of large 

 eyes, spines on pereopods 1-2, and the unusual configuration of the 

 telson (usually with lateral notches or truncate, spinose apices in 

 Elasmopus). The new species is related to E. diplonyx Schellenberg 

 (1938a) by the stout spines of pereopods 1-2; Schellenberg described 

 E. diplonyx with one distal spine; the second spine in the new species 

 is easily overlooked because it does not project bvit overlies the dacty- 

 lus; however, the apically incised telson and stout dactylar spine of 

 E. diplonyx are distinctive. 



