No. 26.] ARTHROSTRACA OF CONNECTICUT. 5 1 



M. Lower lip with principal lobes 

 notched ( Amphithoidae) . 

 N. Without accessory flagellum; uro- 

 pod I with peduncle not produced 



below rami Amphithoe p. 147 



NN. Accessory flagellum present; uro- 

 pod I with peduncle produced 

 to spiniform process below rami 



Grubia p. 151 

 MM. Lower lip with principal lobes en- 

 tire in front (Jassidae). 

 N. Gnathopod 2 in male with propodus 

 having a thumb-like process; in 

 female much larger than gnath- 

 opod I Jassa p. 154 



NN. Gnathopod 2 in male without 

 thumb-like process; in female not 

 much larger than gnathopod i 



Ischyrocerus p. 156 

 KK. Uropod 3 uniramous (Corophiidae). 



L. Uropod 2 uniramous Cerapus p. 159 



LL. Uropod 2 biramous. 



M. Gnathopod 2 in male complexly sub- 



chelate Ericthonius p. 161 



MM. Gnathopod 2 in male simply sub- 

 chelate. 



N. Mandibular palp uniarticulate 



Siphoncecetes p. 168 

 NN. Mandibular palp biarticulate .... 



Corophium p. 170 



LYSIANASSID^. 



Eyes usually large, compound. 



First antennge not longer than second pair; first joint of 

 peduncle tumid ; accessory flagellum always present. 



Mandibles with cutting edge not denticulate; molar tubercle 

 seldom very robust ; palp triarticulate. 



Second gnathopods slender, with ischium elongate, carpus 

 and propodus spinulose, and dactyl minute. 



Terminal uropods biramous. 



Lysianopsis Holmes. 

 Antennge short and differing little in the two sexes. 

 Mandibles edentate, furnished with 3-jointed palp and a small 

 molar process nearer the cutting edge than is the base of the 



