ANNELID GENUS CAMBARINCOLA — HOFFMAN 319 



approximate 23 microns in diameter, while those of the somewhat 

 larger C. philadelphica attained a diameter of only 14 microns in a 

 considerable series of specimens measured. Probably the conversion 

 of this data into some common ratio — such as duct diameter in relation 

 to jaw length — would produce an even more dramatic separation. 



This is the only member of the genus known to be branchiophilus, 

 although C. dtmissa presumably is also. In general, our knowledge 

 of such species is very deficient, owing to the usual necessity of dis- 

 secting the crayfish to extract and examine the gill tissue, and it is 

 entirely reasonable to assume that greater attention to this neglected 

 phase of collection will result in the discovery of additional gill- 

 inhabiting forms. 



Cambarincola shoshone, new species 



Figures 2, 21, 22 



Type specimens. — Holotype and three parat3^pes, USNM 29941, 

 from Pacifastacus gambelii connectans collected in Riley Creek in the 

 Idaho Fish Hatchery near Hagerman, Gooding County, Idaho, by 

 Perry C. Holt, Jul}^ 14, 1958. Topoparatypes from the same collection, 

 PCH 785. 



Diagnosis. — A small species tentatively referred to the Branchi- 

 ophila group, characterized by the distinct and equal-sized deferent 

 lobes, the very short prostate, the very small, isomorphic, homodont 

 jaws, and the graceful, even, body profile. 



Description.- — Maximum length, 1.8 mm., body smallest at 

 segment i, gradually increasing in diameter to segment vii which is 

 also the longest; caudal sucker moderate to large, wider than head or 

 segment i, equal in diameter to segment ii. Prosomites only about 

 twice as long as metasomites, and of the same diameter, the inter- 

 segmental groove very weakly defined. 



Head small, slender, about as long as first three body segments 

 combined, narrower than segment iii, distinctly divided into three 

 subsegments by constrictions; peristomium set off by a very pro- 

 nounced basal constriction, somewhat flared, divided into a small 

 dorsal and a much larger ventral half but otherwise entire and not 

 provided with dorsal lobes. 



Jaws very small, less than 6 percent of the head length, isomorphic 

 and homodont, the dental formula 3-3, each tooth large and con- 

 spicuous. 



Male reproductive system of moderate size, extending dorsad as 

 far as level of gut. Bursa of average relative size, strongly expanded 

 from a narrow ectal portion, the circular muscle region enlarged; 

 penial sheath likewise somewhat expanded as seen in profile. Ejacida- 

 tory duct fairly long and slender, shorter than length of bursa. 



653871 — 63 4 



