THE FAUNA OF BOULDER COUNTY, COLORADO 5 1 



genus new to the United States. This was named in manuscript by Mr. W. P. 

 Hay, but apparently has not yet been published. 



Family GAMMARIDAE 

 First antennae with a small secondary flagellum; fifth peraeopods longer than the 

 preceding; second gnathopods generally larger than the first (Weckel). 



(151) Gammarus Fabricius. Telson cleft; uropods two-branched; inner branch of third 

 uropods not rudimentary, outer one two-jointed. G. limnaeus S. I. Smith has 

 been collected by Mr. G. S. Dodds at Corona and Sulphur Springs. In a lake at 

 Ward I found a Gammarus abundant; I did not examine it minutely, but it is 

 practically certain that it was G. limnaeus. The locality Corona is at the top of 

 the divide, close to the point of junction of Gilpin, Grand and Boulder counties; 

 altitude 11,660 feet. 



Order DEC A POD A Latreille 

 Suborder Macrura Latreille 



Abdomen large, with five pairs of two-branched pleopods, and ending in a tail-fan 

 composed of the telson and the greatly expanded sixth pair of pleopods. 



Superfamily NEPHROPSOLDEA 

 Includes the lobsters and crayfishes. 



Family ASTACLDAE (Potamobhdae) 

 The crayfishes. 



(152) Cambarus Erichson. Last thoracic somite without gills. C. (Bartonius) diogenes 

 Girard.* Boulder. The subgenus Bartonius Ortmann includes species in which 

 the sexual organs of the male are short and thick, the inner and outer part each 

 terminating in only one short and thick spine, tapering to a point; both terminal 

 spines are strongly recurved, forming with the basal part about a right angle 

 (Ortmann). Only the third pereiopods of the male possess hooks. 



The subgenus Cambarus s. str. is represented in New Mexico by C. gallinus Cockerell 



and Porter. 



For an excellent summary of our knowledge of Cambarus, see Ortmann, Proc. Amer. 



Philosophical Society, XLIV (1905). This work includes tables for the subgenera, 



groups and species. 



A very interesting parasitic worm was discovered on Cambarus diogenes by Miss 



Margaret Hankins during the summer of 191 1. Mr. E. Bethel kindly preserved a 



number of specimens, and these have been found by Dr. Max M. Ellis to represent 



a new genus and species. A brief account of the worm follows: 



APPENDIX 



By Max M. Ellis 



A new species of worm, belonging to the Discodrilidae, has been taken from specimens 

 of Cambarus diogenes collected on the University campus. This species, Cambarincola 

 macrodonla, may be recognized by the following characters: anterior nephridia opening 



