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[Vol. 93 
these data continue to support the contention that cave isolation 
does not necessarily result in a permanent reduction in genetic vari- 
ability for a species (Barr, 1968; Giuseffi et al., 1978; Dickson et al., 
1979; Turanchik and Kane, 1979). 
Estimates of P and H by subspecies (Table 2) indicate no differ- 
ences in genetic variability between the four taxa. Of the five polymor- 
phic loci examined, two, EST and PGI, are diagnostic of subspecific 
differentiation (Table 1). Three variants have been detected at each 
of these loci, with all meridionalis populations fixed for a slow 
migrating electromorph at both loci, all viator populations fixed for 
electromorphs of intermediate mobility at each locus, and all hen- 
roti and nominate tellkampfi populations being fixed for the fast 
migrating electromorphs at both loci. The only local population 
that is polymorphic at these two loci is population F (Fig. 1 and 
Table 1). This population, which is morphologically intermediate 
between meridionalis and tellkampfi and a purported hybrid of the 
two subspecies (Barr, 1979b), contains both the slow and fast elec- 
tromorphs at both the EST and PGI loci. The fact that these elec- 
tromorphs are alternatively fixed in meridionalis and tellkampfi 
populations respectively provides biochemical evidence of the 
hybrid nature of this population. By contrast, all three of the viator 
populations are fixed for the intermediate mobility electromorphs at 
both the EST and PGI loci even though two of these populations, C 
and S, lie in the zone of morphological intergradation between tell- 
kampfi and viator { Barr, 1979). 
Rogers’ (1972) estimate of genetic similarity (S) was used for 
pairwise comparisons of the 18 populations (Table 3). Rogers’ dis- 
tance values were used in a UPGMA clustering procedure to pro- 
duce a biochemical dendrogram (Fig. 2). Infrasubspecific genetic 
identities are all greater than 0.90. This includes some populations, 
such as the C population of viator, separated from other popula- 
tions of the same subspecies by shallow rivers such as the Green 
River. This finding is consistent with earlier work (Turanchik and 
Kane, 1979) on populations BH, RB and B of nominate tellkampfi 
and with findings on at least one other cave limited species in the 
same area (Laing et al., 1976), and serves to reconfirm the fact that 
rivers per se are not necessarily dispersal barriers for cave limited 
forms. Genetic differentiation between subspecies is substantial in 
some cases (Fig. 2). Neaphaenops t. meridionalis and N. t. viator 
