FISHES OF CHESAPEAKE BAY 
35 
Glanostomi (the sturgeons). 
a. Skeleton cartilaginous; snout produced, with four flexible barbels; mouth underneath; teeth 
wanting; skin imperfectly covered with bony plates Acipenseridx (sturgeons), p. 72 
Holostei (the gar pikes). 
aa. Skeleton bony; both jaws greatly produced, armed with sharp teeth; no barbels; skin com- 
pletely covered with rhombic plates Lepisosteidx (gar pikes), p. 77 
Teleostei (nonganoid fishes) : Tail homocercal or isocercal (not heterocercal) ; arterial bulb 
thin, with a pair of opposite valves. 
A. Ventral fins present, abdominal. 
a. Dorsal fin single; adipose fin present or wanting. 
b. Adipose fin wanting. 
c. Pectoral fins inserted low on side, below axis of body; lateral line, when present, nor- 
mally placed; lower pharyngeal bones separate. 
d. Gill openings restricted, the membranes attached to the isthmus; jaws without teeth. 
Eventognathi (suckers, carps, and carplike minnows). 
e. Maxillaries forming sides of margin of upper jaw; lower pharyngeal bones armed 
with a single row of comblike teeth Catostomidx (suckers), p. 117 
ee. Premaxillaries alone forming margin of upper jaw; lower pharyngeal bones 
supporting one to three series of teeth, the teeth few in number 
Cyprinidx (carps and minnows), p. 120 
dd. Gill openings not restricted, the membranes free from the isthmus; teeth in jaws 
present or absent. 
/. Head naked; dorsal fin more or less over the middle of the body; upper jaw 
not protractile; color silvery. 
Isospondyli (the clupeoid and salmonoid fishes). 
g. An external bony plate present between the arms of the lower jaw; lateral 
line present. 
h. Scales comparatively small; pseudobranchiae present, large; the last 
ray of dorsal not produced Elopidx (10-pounders), p. 78 
hh. Scales very large, pseudobranchiae absent; last ray of dorsal greatly 
produced, filamentous Megalopidx (tarpons), p. 79 
gg. No bony plate between the arms of the lower jaw; lateral line absent. 
i. Body oblong or elongate; mouth small to moderate, terminal or slightly 
superior, oblique; stomach not gizzardlike. Clupeidx (herrings), p. 81 
ii. Body rather short and deep; mouth small, inferior, terminal; stomach 
gizzardlike Dorosomidx (gizzard shad), p. 106 
Hi. Body elongate; mouth large; snout pointed, usually projecting far 
beyond mandible; stomach not gizzardlike 
Engraulidx (anchovies), p. 108 
//. Head scaly; dorsal fin commonly posterior in position; upper jaw protractile 
or not; color not silvery. 
Haplomi (the pikelike fishes). 
j. Body very elongate; snout considerably produced, depressed; mouth 
large; maxillaries forming sides of upper jaw; size moderate to 
large Esocidx (pikes and pickerels), p. 132 
Cyprinodontes (the killifishes and top minnows). 
jj. Body oblong or moderately elongate; snout not produced; mouth 
small; premaxillaries forming entire margin of upper jaw; size 
small. 
k. Anal fin similar to the dorsal and not modified in the male; species 
oviparous Cyprinodontidx (killifishes), p. 134 
kk. Anal fin in the male modified, some of the rays produced, others 
short and more or less coalesced, the fin serving as an intromit- 
tent organ; species viviparous.. Poeciliidx (top minnows) p. 145 
