BULLETIN FLORIDA STATE MUSEUM


age less for a number of characters, particularly depth of body, depth
of head, and distance from dorsum to lateral line (table 6). Also
depth of caudal peduncle, length of head, mouth gape, width of body,
width of head, width of eye, length of upper jaw, and all fin lengths
average proportionately slightly less; the caudal peduncle, on the
other hand, averages slightly longer. Although these differences
are usually rather marked, atypical specimens can be found in both
the northern and southern populations (figure 10).
 Morphological differences of the above magnitude exist among
individuals of N. cornutus. In that form these differences can always
be explained by environment, slender-bodied fish usually being found
where a shortage of food exists. As food is apt to be scarcer in cool,
relatively sterile northern streams, slender-bodied individuals of cor-
nutus tend to occur to the north. The morphological differences in
albeolus cannot be explained by environment. While streams of the
Roanoke and New River systems are in general clearer, swifter, and
presumably somewhat more sterile than those of the Neuse, Tar, and
Cape Fear drainages, this can hardly explain such sharp differences in
body proportions. In addition the closely related Notropis cerasinus,
a common species in the headwaters of the Roanoke, is characterized
by a body form fully as deep and compressed as either that of N.
cornutus or of the southern population of N. albeolus. This strongly
suggests that the differences in body form in albeolus have a genetic
rather than an environmental basis. Consequently N. albeolus may
best be regarded as containing two distinct races, one inhabiting the
New and Roanoke drainages, the other the Neuse, Tar, and Cape Fear
systems.
 The slight difference in scale counts between the two races is sub-
ject to considerable overlap. Table 7 shows specimens from the
New and Roanoke drainages average about one scale more in the
dorso-lateral and circumferential scale series than do those from the
other systems. The upper limit (55) for this count in specimens from
the more northern drainages is 4 more than for specimens from the
Neuse, Tar, and Cape Fear; the lower limit (42) is 1 more.
 The crescent-shaped markings that occasionally appear on the
side of the body are more common in specimens from the southern
drainages. Other kinds of variation apparently occur equally in
both races.
 The lack of red pigment on both the body and fins, including the
breeding males, is one of this fish's most distinctive characters.
Though this feature holds true most of the time, Robert D. Ross in-
forms me in a letter that occasionally breeding males from both the


Vol. 8