THE CRUSTACEA OF NEW JERSEY. 341 



Ortiiiannicus is here proposed as a new subgeneric name, the 

 intended Bartonius Ortmann being- an exact synonym of Caui- 

 banis. Ortuiannicns will thus embrace the limits as defined by 

 Bartonius. This is offered as a slight tribute to Dr. Ortmann's 

 recent studies of the crawfishes, which are among; the most 

 important and comprehensive yet attempted. 



Key to the species. 



a. Male sexual organs with both parts, outer and inner, each ending in only 

 one tooth, which rather slender, not sharply distinguishable from end. 

 and never truncated. 



b. (Cambarus) Male sexual organs very uniform, short, thick, inner and 

 outer part each end in only one short thick spine, tapering to point ; 

 both terminal spines strongly recurved, forming with basal part about 

 right angle ; third persopods, in male only, with hooks ; rostrum 

 always without marginal spines ; carapace generally without lateral 

 spines. 

 c. Areola wide; carapace depressed; species of small streams. 



barton a 

 cc. Areola narrow, generally obliterated in middle, or extremely nar- 

 row ; carapace rather depressed. diogenes 

 bb. (Faxonius) Male sexual organs shorter or longer, not very stout, 

 generally slender or with slightly curved tips ; tips never truncated, 

 end always in two more or less elongated spines, one formed by outer 

 part and other formed by inner part softer ; never more than one tip 

 to outer part and no terminal tooth distinguishable, but tip tapers 

 gradually and whole outer part setiform; third peraeopods, in male 

 only, with hooks, very rarely on third and fourth pairs; rostrum 

 always with marginal spine on each side : carapace with one or more 

 lateral spines. limosus 

 aa. (Oktmannicus) Male sexual organs stout, more or less straight, com- 

 paratively short, truncated or blunt at tip, outer part ending in one to 

 three horny teeth, which sometimes recurved or compressed, or plate-like, 

 and always sharply distinguishable from blunt end; inner part ends by 

 shorter or longer acute spine, which sometimes distinct from tip of this 

 part, so that it appears two-pointed; third, or third and fourth, perseopods 

 in male with hooks. blandingii. 



Cambarus bartonii (Fabricius). 



Plates ioo and ioi. 



Barton's Crawfish. Mountain CrauHsh. 



Brook Crawfish. 



Astacus bartonii Fabricius, Entomol. Syst. Suppl., 1793, p. 407. North 

 America. (Likely Philadelphia.) 



