ANNELID GENTJS CAMBARINCOLA — HOFFMAN 317 



deferent lobe. The prostate is rather short p.nd histologically similar 

 to the spermiducal gland. There are no appreciable specializations 

 aside from the modification of the nominotypical species for inhabiting 

 the branchial chambers and gills of the crayfish. 



It is here that we encounter extremely localized forms: Each of the 

 species is known only from one locality. Their specific distinctness 

 certainly suggests that they must be relicts of a former mde-ranging 

 stock, rather than recent derivatives of an existing progenitor. 



Cambarincola branchiophila Holt 



FiGUBES 23, 24 



Cambarincola branchiophila Holt, 1954, Virginia Journ. Sci., new ser., vol. 5, pp. 

 168-172, figs. 1-5. — Holt and Hoffman, 1959, Journ. Tennessee Acad. Sci., 

 vol. 34, p. 103. 



Type specimens. — Holotype, USNM 25855, from Cambarus har- 

 tonii and C. sciotensis collected in Sinking Creek, Giles County, Vir- 

 ginia (one mile west of Newport), by P. C. Holt, F. D. Kiser, and 

 Cornelia Tuten, July 3, 1950; topoparatypes, PCH 407, from the 

 same collection. 



Diagnosis. — A moderately large species of its group, characterized 

 by the stout body form, 5-5 dental formula, and generally reduced 

 male reproductive system, without the strongly shortened prostate 

 gland which characterizes Cambarincola shoshone. 



Description. — Body stout, up to about 3.5 mm. in length, segment 

 I narrowest, following segments increasing up to vi and vii which 

 are twice the diameter of i; last three body segments abruptly de- 

 creasing in size, caudal sucker subequal in diameter to segment i. 

 Segments short, the prosomites about twice the length of metasomites 

 but not elevated above them. 



Head relatively small, only slightly longer than broad; its diameter 

 less than that of segment i; peristomium set off by a distinct basal 

 constriction, flared but with entire margins, no evidence of lobes in 

 preserved specimens. Basal portion of head subdivided by a shghtly 

 impressed constriction and thereby appearing superficially tripartite 

 in profile. 



Jaws small, essentially isomorphic; heterodont, the dental formula 

 5-5 with the paramedian cusps of each jaw slightly smaller than the 

 large median and outer dentations. 



Alale reproductive system reduced in overall size and confined to the 

 lower third of one side of the segment. Bursa obovate to fusiform, 

 about as long as the slender ejaculatory duct; spermiducal gland small, 

 somewhat flattened, with two subequal deferent lobes; prostate gland 

 fairly broad, slightly enlarged entally, extending as far as the sinus 

 between the deferent lobes. 



