314 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ii4 



distinctly tripartite, and suggest tiie condition upon which Goodnight 

 founded a genus Triannulata. More caudal segments appear normal, 

 e.g., with two subsegments. 



Relationships. — The affinities of macrocephala lie rather clearly 

 with the very similar C. holti from central Kentucky, which differs 

 in its smaller size, particularly that of the head, and longer glandular 

 organs of the male reproductive system. That the similarities of the 

 two are due to convergence seems unlikely, and it is possible that 

 we are here confronted with two relict forms of a parental stock which 

 extended widely across North America during mid-Tertiary times. 



Distribution. — Known only from two mdely separated localities 

 in the upper part of the Snake River drainage. Collected, in addition 

 to the type locality, at the following station: 



Idaho: gooding county: Riley Creek at the Idaho Fish Hatchery, July 14, 

 1958, P. C. Holt (PCH 785). At this locality it occurred on Pacifastacus gamhelii 

 connectans. 



Remarks. — Assignation of the Idaho specimens to Goodnight's 

 name macrocephala is made here with some reservation. Several 

 differences shown by the type of the species have been noted in a 

 preceding paragraph, and are illustrated in the accompanymg figures. 

 Until fresh topotypes of macrocephala are obtained for study, there 

 will remain some doubt about its identity, but the general similarity 

 of the worms from the two localities is so great that I think a con- 

 servative approach is warranted here. Although the male sex organs 

 of the holotype can be seen only in dorsal aspect, they seem to cor- 

 respond to those of the specimens from farther down the Snake River. 



Presumably the original spelling "macrocephela" is due to a typo- 

 graphical error. The meaning, "long-headed" is particularly appro- 

 priate for a worm in which the head is one- third the entire length of 

 the animal! 



Camharincola holti, new species 



Figures 18, 20 



Type specimens. — Adult holotype and paratypes of various ages, 

 USNM 29940, from Camharus sp. collected in a stream on the southern 

 edge of Somerset, Pulaski County, Kentucky, by Perry C. Holt, 

 July 28, 1958. 



Diagnosis. — A moderately large worm generally similar to macro- 

 cephala in body form and proportions, but distinct in the dental 

 formula (5-4), abruptly flexed spermiducal and prostate glands, and 

 characteristicall}^ shaped spermatheca. 



Description. — Maximum size of preserved worms (holotype), 4.1 

 mm. in length, 0.9 mm. in diameter at segment viii, 0.7 mm. in greatest 

 head width. Body outline of the usual form, segments v-vii of es- 



