STATE GEOLOGIST. llT 



Characters. — Clasping organs three-jointed; egg-pouch short, broad; living in 

 more or less saline waters. 



The members of this genus, which will be often referred to, are peculiarly 

 interestmg from the way in which they show the great and sudden changes that 

 a change in the invironment, is competent to effect in animal forms. 



Three species are known m the United States, one of which is found in the 

 eastern states, another m Utah, and still another in California, viz: gracilis^ 

 monica, Bud fertilis. 



SUB-FAMILY EULEMENIN^. 



Characters. — Abdomen almost obsolete; both pairs of antennae filiform. 



GENUS Eulimene. (Latreille.) 



FAMILY NEBALID^. 



Characters. — Antennae large and ramiform; eyes peduncled; feet twelve pairs; 

 carapax large, enclosing head, thorax and part of the abdomen, 

 as in a bivalve shell. 



UENUS Nebalia. 



Bibliography. — Nebalia, Leach, Thompson, Desmarest, Latreille, M. Edwards^ 

 ^ Bosc, Lamarck, etc., etc. 



Cancer, 0. Fabricius, Herbst.. 

 Monoculus, Montagu. 

 Myses, Olivier. 

 Being the only genus in the family, the above characters also characterize the 

 genus. 



TRIBE II. APHODOIDEA. • 



Bibliography. — Apusiens (in part), Edwards. 

 Apodidse, Biirmeister. 

 Baird. 



Characters. — Body straight; cephalothorax covered by a scuteliform shell; pos- 

 terior appendages of the thorax lamalliform; abdomen many- 

 jointedj eyes sessile. 



FAMILY Apodidse, 



Bibliography. — Apus, M. Edwards, Hist. Nat. Crust., iii., 356. 



Phyllopoda, Leach, Edin. Enc^'clop. VII., art. Crustaceology. 



Apodidee, Burmeister, organization of Trilobites, 34. 

 Characters. — Of large size, with a rounded carapace partially covering the base of 



the abdomen, which is elongate and ends in two many-jointed, 



caudal filaments; about sixty pairs of swimming feet; antennae 



rudimentary; first maxillipeds antenniform. 



