BULLETIN FLORIDA STATE MUSEUM


 VARIATION. Geographical variation is noteworthy only in number
 of anal rays, pigmentation on chin and gular area, and in size of an-
 terior dorso-lateral scales. No where is variation consistent enough
 to be deemed worthy of taxonomic
 Recognition.
 S A Populations in Maine, Nova
 Scotia, and, presumably, New
 Brunswick often have many indi-
 viduals (usually 40 to 60 percent)
 with 8 anal rays, a variation found
 only occasionally in other parts of
 the range (table 13). An analysis
 of other morphological characters
 from the Maine-New Brunswick-
 Nova Scotia area reveals surpris-
 ingly low anterior dorso-lateral and
 circumferential scale counts (table
 7), though, as discussed below, they
 fall within the overall variation of
 this form. In no other way do
 SB these fish differ from typical cor-
 nutus.
 ) The chin and anterior part of
 the gular area are unpigmented in
 populations west of the Appala-
 chian Mountains, but this character
 shows little apparent consistency in
 populations east of the Appala-
 chians. Only in the upper Sus-
 quehanna River system is pigment
 consistently absent and, as dis-
 cussed in the zoogeographical sec-
Figure 9. A. Notropis cornutus. In- tion, this is of value in determining
dividuals living west of the Alle- phylogenetic relationships. There
ghenies usually lack pigment on the c b l d t t
gular areas and most of the chin; can be little doubt that this charac-
those from the Atlantic side often ter is largely under genetic control,
have pigment here. B. Notropis a premise substantiated by the fact
chrysocephalus chrysocephalus. This that this part of the head usually is
pattern remains rather consistent pigmented in specimens of N.
throughout most of the range of this chrysocephalus living sympatrically
form. It is often lacking in speci-
mens from the Tennessee River drain- with N. cornutus. In many popu-
age. lations over the northern part of the


Vol. 8