116 ORTMANN — AFFINITIES OF CAMBARUS. [April 13, 
the changes of the drainage systems in the southern Appalachians, 
see: Simpson, Sczence, 12, 1890, p. 133, and chiefly Adams, 
Americ. Natural., 35, 1901, p. 844 ff.; where on p. 849 three 
species of Cambarus are mentioned (C. sfinosus, extraneus, and 
erichsonianus) that belong into this category). The species C. 
neglectus, hylas, and medius belong to the southwestern and western 
edge of the range of vwsticus, and are found in Missouri, Arkansas, 
Texas, Kansas, and Iowa. ‘Thus it is evident, that the six species 
morphologically allied with C. rusticus in the same group, express 
this relation also in their distribution, being apparently locally 
modified forms of the rusticus-type, and being naturally found 
just where we ought to expect them, namely at the edge of the 
range of this vws¢zcus-type. 
C. erichsonianus seems to be abnormal : morphologically we have 
placed it with C. propinguus, but its range is far remote from it in 
eastern Tennessee and central Alabama (in both the Tennessee 
and Alabama river drainages). But, as we have seen above, its 
position is a little uncertain, it resembling C. vws¢icus and its allies 
to a degree, and the distribution suggests the same: it clearly 
agrees better in this respect with C. forceps and spfinosus, and it 
would thus become another local form of the vws¢écus-type. Fur- 
ther investigations on this question should be made. 
The third section, that of C. virtlis, has been divided into three 
groups. The wr7/is-group agrees somewhat with the rusticus-group 
in its range, belonging to the central basin, only being a little 
more western, and considerably more northern: it is hardly found 
in the drainage of the Ohio, but it is very abundant in that of the 
Mississippi and Missouri, and crosses over not only into the lake 
drainage, but also into that of Hudson Bay (Winnipeg Lake). 
The typical species of the group (vzrz/is) occupies almost all of 
this range, while four other species associated with it (meekz, longt- 
digitus, nats, pilosus) apparently are local forms of it, being found 
at or near the southwestern extremity of the range of C. wirzlis 
in Arkansas and Kansas. C. émmunis is a peculiar type of the 
virtlis-croup, and its range coincides with the southern part of the 
range of C. wirtlis (Kansas, Missouri, Iowa, Illinois, Indiana, 
Ohio): this is interesting in’so far as this occupation of the same 
territory by two closely allied species is rendered possible as it 
seems in this case, by the different habits: as far as we know, C. 
