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PROCEEDINGS OF THE NATIONAL MUSEUM 



Figures 21-24. — Structural details of two species of the Mesochorea section. 21, Cambar- 

 incola shoshone, new species, paratype, Gooding Co., Idaho; 22, the same, reproductive 

 systems in lateral aspect. 23, C. hranchiophila Holt, paratype, Giles Co., Virginia; 

 24, the same, reproductive systems in lateral aspect. Figures 21, 23 and 22, 24 drawn 

 to same scales. 



Spermatbeca simple, a slender tubular structure, witb a fairly 

 sbort, muscular ectal third and a sligbtly tbicker glandular ental 

 two-tbirds; no ental process present. 



Variation. — Tbe only appreciable variation observed in tbe 

 small number of worms available from tbe type locality affects tbe 

 proportions of tbe bm'sa, specifically its lengtb to diameter ratio. 

 Presumably sucb variation is a consequence of muscular reaction to 

 preservation. 



Affinities. — Superficially tbis species bears a strong resemblance 

 to C. shoshone, although the similarity may be a result of convergence. 

 In my opinion, C. hranchiophila is a relict of some extinct ancestral 

 stock, and does not have any really close relatives among the known 

 existing species. 



Distribution. — Known only from the type locality, but certainly 

 to be expected elsewhere in the Kanawha River drainage of south- 

 western Virginia. 



Remarks. — In the original description, Holt cites some measure- 

 ments of interest. He found that the deferent ducts of this species 



