66 PEOCEEDIlsrGS OF THE NATIONAL MUSEUM. vol. 60 



First antennae short and stout, five- to seven- jointed, the basal or 

 subbasal joint usually armed with curved claws. Second antennae 

 three- jointed, the terminal joint a stout curved claw. Mouth tube 

 small, conical, and bluntly rounded ; mandibles slender, stylet-shaped ; 

 first maxillae biramose, rami slender and fringed with hairs ; second 

 maxillae three- jointed, the last joint a small claw; maxillipeds large, 

 with strong terminal chelae. First four pairs of legs short, biramose ; 

 rami of first pair two-jointed, of second, third, and fourth pairs three- 

 jointed ; exopod of second pair often modified ; fifth pair uniramose, 

 one-jointed. Anal laminae short but well armed with setae; egg 

 strings as long as the body ; eggs large, not much flattened. 



GeneHc characters of male. — General body form and segmentation 

 as in the female, but smaller, longer, and more slender. Genital seg- 

 ment and abdomen together forming half the entire length, the former 

 considerably larger than the fifth segment. Abdomen three- or four- 

 jointed. 



First antennae stout, with a strong curved claw at the tip ; second 

 pair also stout, with two large terminal claws and spines on the first 

 two joints. Maxillipeds with a normal basal joint and a long termi- 

 nal claw not chelate. Swimming legs like those of the female, except 

 that the second exopod is not modified. Anal laminae long and nar- 

 row, tipped with hooked claws. 



Tyj)e of the genus. — Eudactylina acuta P. J. van Beneden, mono- 

 typic. 



KEY TO THE SPECIES. 



1. Entire body rough and covered with short, coarse hairs; second thorax 

 segment not sensibly smaller than the others 2 



1. Entire body smooth, without hairs or spines except on the appendages; 

 second thorax segment distinctly smaller than the others 4 



1. Frontal end of carapace and two abdomen seginents covered with spinules ; 



fourth and fifth segments fused insolens T. and A. Scott, 1912 



2. Free thorax segments considerably wider than long; egg strings elongate 



and filiform ; eggs minute and strongly flattened 3 



2. Free thorax segments as long as wide or longer ; egg strings wide and short ; 



eggs large, not much flattened minuta T. Scott, 1904 



3. Head triangular, narrowed to a rounded point anteriorly ; second, third, and 



fourth segments wider than the head, obcordate ; abdomen four-jointed; 

 anal laminae wide, flattened sqiiatinae-angeli Hesse, 18S3 



3. Head tetragonal, narrowed but little anteriorly; second, third, and fourth 



segments transversely elliptical; abdomen two-jointed; anal laminae 

 slender and cylindrical aspera Heller, 1SG5 



4. Head oblong, narrowed anteriorly; maxillipeds strongly chelate, jaws about 



equal, their ends shutting together 5 



4. Head quadrate, as wide anteriorly as posteriorly; maxillipeds not chelate, 



claw longer than basal joint and shutting against a knob 6 



5. Second segment cousiderably smaller than the others; anal laminae broad 



and flattened, eacl; with three rudimentary spines and a fringe of hairs on 

 the inner margin- acuta P. J. van Beneden, 1853 



