2a. (From 1a.) Cephalic sensory canals on head below eye and on lower jaws large and appearing as distinct chambers colored as in mother-of-pearl (in life).
silverjaw minnow
Notropis buccatus

2b. (From 1a.) Cephalic sensory canals on head small and inconspicuous and not appearing as mother-of-pearl (in life).

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