STATE GEOLOGIST. . 83 



Beak cleft below or with a forward projection. 



(a) Aiitennules shorter than the beak. 



5. C. Ulljeborgii, SCHOEDLEB. 



(b) Antennules longer than the beak. 



6. C. rotundv^, HEBBICK. 



Sp. 1. Camptocercus biserratus, Schoedler. 



(Plate I. Fig. 4.) 



Is very nearly related to the next, from which it is distinguished 

 chiefly by the fact that the pigment fleck is larger than the eye. 

 Schoedler overlooked the fact that in C. macrurus there is a lateral 

 line of scales on the abdomen, and relied upon that character to 

 distinguish this form. (Schoedler says that the pigment fleck in C. 

 macrurus is smaller than the eye, P. E. Mueller says they are nearly 

 equal, while in our specimens they are much smaller or nearly 

 equal.) If much variability is found, Schoedler's species seems to rest 

 on a slender basis. The basal spine of the claw, however, seems to 

 be peculiar in sitting on a distinct prominence. 



Sp. 2. Camptocercus macrurus, Mueller. 

 (Plate E. Fig. 10.) 



Lynceus macrurus, LILLJBBOBG, SCHOEDLEB, P. E. MUELLEB, KUBZ, BIBGE, HEBEICK. 



This universally distributed species occurs in our larger bodies 

 of water and is not rare, though hardly abundant. 



The body is long and nearly rectangular; the head strongly 

 arched and keeled. The keel of the head is extended down the 

 whole dorsal line. The dorsal line is moderately curved, while the 

 shell is but slightly excavated below. The head extends into a 

 blunt beak looking downward; the direction of the head is some- 

 what variable (from vertical to an angle of about 30°). The eye is 

 much larger than the pigment fleck; the antennules are shorter 

 than the beak, and have one elongated terminal seta. The post- 

 abdomen is very long and has numerous anal teeth as well as a 

 lateral row of scales. The basal spine of the claws is large and ser- 

 rate, the claw itself being nearly straight and armed with an in- 

 creasing series of spines to beyond the middle. The lateral scales 

 of the post-abdomen are inconspicuous. The shell gland is long. 

 The antennules reach to almost the end of the beak, are curved and 

 bear a lateral flagellum. The first foot of the female has a sort of 

 hook (branchial sac?). The labrum is armed with teeth on the 

 posterior face of the triangular process. The intestine is very 

 trongly, almost twice coiled. The lower margins of the valves are 



