ANNELID GENUS CAMBARINCOLA— HOFFMAN 



331 



Figures 35-38. — Structural details of two species of Cambarincola. 35, C. virginica, ex- 

 ternal appearance of holotype, Chesterfield Co., Virginia (somewhat distorted in 

 preservation); 36, the same, reproductive systems in lateral aspect. 37, C. macrodonta 

 Ellis, lateral aspect of paratype, Boulder Co., Colorado; 38, the same, reproductive 

 systems in lateral aspect. 



and the Carolinas, the dorsal jaw is invariably the longer, amounting 

 to 8 or 9 percent of the head length. There is unfortunately nothing 

 available in the way of good material from north Georgia, so we can- 

 not say whether this variation represents merely a north-south gradient 

 or whether some break in the distribution of the character occurs (as 

 possibly at the Savannah River). It will be recalled that in vitrea, 

 variation in the ratio of jaw length to head length proceeds in just 

 the opposite direction, the jaws becoming smaller in going north from 

 Arkansas to North Dakota. 



This relationship casts an interesting reflection in the matter of the 

 status of vitrea and osceola. In the former population (and assuming 

 the two to be aUopatric species), the jaw size increases from the 

 farthest periphery toward the general direction of osceola, in the 

 latter, the jaws decrease in size in going from Virginia south and west 

 in the direction of vitrea. There is perhaps an even continuum of 

 the 6-8 percent ratio between the populations of the Ozarks on one 

 hand and west Florida on the other, which, if proved, would result in 

 a great crescent ranging from North Dakota to southeastern Virginia, 

 with the JL/HL ratio only 5 percent at one extreme, but increasing 

 to 9 percent at the other. 



