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Description: Body relatively thin, long and narrow with a large eye and a terminal mouth. Paired fins medium to long at transition, dorsal and anal-fin bases relatively short, caudal peduncle long and narrow, procurrent caudal-fin rays 7-10 (7-9 spindly). Lightly marked mostly along the lower body: melanophores on the ventral midline at the isthmus and the pelvic-fin insertion (usually streaks). Then there is a row along the anal-fin base, usually six or often seven, paired and one per side between the third and ninth element (often merged into a streak on each side). Then after a space there is a row of midline melanophores, usually seven, sometimes eight, unpaired (but often merged into a streak), extending along the caudal peduncle ending near the start of the procurrent caudal-fin rays. Internal melanophores are present at the dorsal surface of the swim bladder and around the gut near the vent (none on the head). Series of transitional larvae show development of the eye from a slightly narrowed vertical oval slightly tilted forward with a small posterior-inferior extension of the iris to round and notably larger. The extension has several surface melanophores overlying it (vs. C. glaucofraenum, comparative photograph below). Rare individuals show abnormal enlargements of this extension. There is often a prominently speckled "eyebrow" membrane over the upper half and posterior of the eyeball that appears detached from the pigmented iris below. Transitional larvae develop a scattering of iridophores between the eyes and in a stripe behind the upper eye. Melanophores start as a few scattered on top of the head developing into a loose cluster on the dorsal surface of the head behind the eye (not a stripe). Melanophores later develop in a tight group on the abdominal wall forward of the vent.