BULLETIN FLORIDA STATE MUSEUM


congeners, they are inclined toward places where small enclosures abound.
 A population of Chasmodes saburrae in the Everglades inhabits waters
that become less saline (down to 5.5 ppt) than those inhabited by the other
populations. The combination of this and other environmental factors yet
to be determined has apparently resulted in a slight increase in number of
mandibular teeth in this population (Table 6). This slightly higher number
of mandibular teeth (Fig. 4) than most other populations (Table 6) is the
only character that shows measurable differences (statistical or otherwise).
In addition, I have not examined specimens from the area between the
southern tip of peninsular Florida and Charlotte Harbor (Fig. 5). This
suggests the possibility that the Everglades population is isolated (i.e. no
gene flow) from the Charlotte Harbor population. Although possible, the
existence of estuarine habitat, suitable for Chasmodes, between these areas
argues against this type of isolation. I believe that this disjunction is a
collecting artifact, since most of this area is accessible only by boat and has
apparently not been well sampled.
 This difference of the Everglades population from the others is not
unique to the genus Chasmodes. Weinstein and Yerger (1976) commented
on the disparity between the Everglades "subpopulation" of Cynoscion
nebulosus and other subpopulationss" of that species. In an attempt to
explain this difference, they suggested that it results from environmental
factors unique to that area.
 Relyea (1967) presented data on an Everglades population of Fundulus
confluentus that clearly show a trend toward an increase in number of
elements in numerous meristic characters, although Relyea made no com-
ment on this disparity.
 Life history and reproductive strategies of Chasmodes saburrae are
discussed by Peters (1981), and thus are not treated in this work.
 Chasmodes saburrae occurs from Edgewater, Volusia County, Florida,
southward around the southern tip of the state, northward and westward as
far as the Chandeleur Islands, Louisiana. I have examined three young
specimens (8.9 to 9.8 mm SL, collected on 27 May 1935, USNM 188254)
from Matanzas River, Florida. Based on their small size and the fact that no
other C. saburrae have been collected this far north on the east coast of
Florida, I believe that these three specimens were wafted northward
during their planktonic larval stage. Kevin Peters (pers. comm.) has
informed me that C. saburrae larvae settled out of the plankton in three
weeks under ideal conditions. This length of time would be sufficient to
allow the larvae to drift from more southerly waters to Matanzas River,
assuming a drift rate of approximately 3 to 4 miles a day. The absence of
sexually mature C. saburrae in the Matanzas River indicates that this
species does not normally occur this far north, and this region is therefore
not considered to comprise a normal part of the range of the species. In


VOL. 29, NO. 2