Pirate perch is a stout, dark-colored fish, with a single dorsal fin and ctenoid scales on the head and body. From Wordnik.com. [Think Progress » “When I caught a 7.5 pound perch in my lake”] Reference
I tried to follow Agassiz's scheme of division into the order of ctenoids and ganoids, with the result that I found one of my species of side-swimmers had cycloid scales on one side and ctenoid on the other. From Wordnik.com. [Louis Agassiz as a Teacher; illustrative extracts on his method of instruction] Reference
The distinction between the ctenoid scale types, therefore, is primarily based upon their form. From Wordnik.com. Reference
Cycloid Fish Scale - The primary types of fish scales include placoid, cosmoid, ganoid, ctenoid, and cycloid scales. From Wordnik.com. Reference
Thin, translucent, and lacking enamel as well as dentine, these modern structures are known as cycloid and ctenoid scales. From Wordnik.com. Reference
Basic ctenoid scales, on the other hand, exhibit ctenii, which are formed as separate bony growths distinct from the main body of the scale. From Wordnik.com. Reference
So long as the strongly-armed ganoidal order prevailed in nature, the sharks were furnished with massive crushing teeth; but when the ganoids waned in creation, and the soft-scaled cycloid and ctenoid orders took and amply filled the place which they had left vacant, the well known modern form of sharks 'teeth was introduced, -- a form much rather suited for cutting soft bodies than for crushing hard ones. From Wordnik.com. [The Testimony of the Rocks or, Geology in Its Bearings on the Two Theologies, Natural and Revealed] Reference
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