340 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 114 



In the belief that philadeljjhica was both homoguathous and 

 heterognathous, tentaculate as well as not, Goodnight identified 

 Virginia worms submitted to him in 1948 by P. C. Holt as typical 

 of that species. On the basis of this information, Holt published in 

 1949 an account of the reproductive organs of the species, under the 

 name philadelphica, although subsequent examination of his slides 

 indicates that actually the material is mostly Jallax. That a single 

 species should encompass such variability, however, appeared un- 

 likely to Holt, and he subsequently (1951) expressed some doubt 

 about the correctness of Goodnight's determination in a discussion of 

 worms from piedmont Virginia which had been named as philadelphica. 



On the basis of a great number of specimens examined from numer- 

 ous localities throughout the Appalachian region, I must conclude 

 that jaw shape is a constant and reliable specific character, and is 

 correlated with other structural specialties of a less conspicuous, but 

 no less significant nature. 



Two new species are herein added to the Philadelphica group, and 

 there is every reason to assume that others will be disclosed by the 

 future location of isolated endemic forms as well as by the analysis of 

 more abundant material from eastern United States. The nominate 

 species itself is almost certainly polytypic, as discussed in connection 

 with the species. A number of variant forms in this general complex 

 are omitted from present consideration, being known only from 

 single specimens or poorly preserved material. 



The following key to species should be approached like most 

 keys — as an aid in identification rather than as the source of ultimate 

 authority. Actually, this and other keys in the present paper are 

 provided largely in order to give a tabular view of species grouped 

 somewhat according to their presumed relationships. No key is as 

 satisfactory as pictures when taxonomic characters are highly subjec- 

 tive ones! 



Cambarincola meyeri is, with the utmost reluctance, entered as a 

 member of both subgroups, owing to its poorly understood characters. 

 See the discussion of this matter under the specific heading on page 355. 



Key to Species of the Philadelphica Group 



1. Homognathous species, the two jaws similar in size and shape, the median 



tooth always much larger than the laterals, dental formula 3-3 or 5-5 



(Fallax subgroup) 2 



Heterognathous species, the jaws dissimilar in shape and often also in size; 

 the dental formula 3-4, 5-4, 1-2, or a similar combination of odd (dorsal) 

 and even (ventral) numbers of teeth (Philadelphica subgroup) ... 4 



2. Peristomium obviously tentaculate; prostate virtually as long as spermiducal 



gland (Appalachian Mountains and adjacent Piedmont areas from western 



New York to central Georgia) .... Cambarincola fallax, new species 



Peristomium entire or nearly so, no trace of lobes or tentacles 3 



