SOME FEATURES OF ORNAMENTATION IN THE 

 KILLIFISHES OR TOOTHED MINNOWS 



HENRY W. FOWLER 

 The Academy of Natural Sciences of Philadelphia 



The killifishes, so named by the early Dutch settlers 

 about New York from their habit of living in the channels 

 or kills, embrace an interesting family of fishes. They 

 are known by other names, as top-minnows, cyprinodonts, 

 toothed minnows, millions fish, etc. Some of these names 

 are, however, more limited in scope and pertain to sec- 

 tions or genera. Top-minnow was applied from the habit 

 of many living at the surface, and cyprinodont, meaning 

 toothed carp, arose as some greatly resemble very small 

 carps or true minnows (Cyprinidae), though were found 

 to differ in the presence of teeth in their jaws. Besides 

 this character are a number of others, in which they agree 

 with several related families to form the order of pike- 

 like fishes (Haplomi). Such are all internal and largely 

 have reference to the bony skeleton. In the abdominal 

 ventral fins (Procatopus excepted), and without true 

 spines in the dorsal and anal fins, the order resembles the 

 herring-like fishes (Isospondyli), but differs in the ab- 

 sence of a mesacoracoid bone. This latter character is in 

 agreement with the host of spiny-rayed fishes (Acanthop- 

 teri), but they usually have the ventral fins well anterior. 



Though six families are included in the order of pike- 

 like fishes, only the mud-minnows (Umbridae) and the 

 pikes (Esocidai) occur in the Middle Atlantic States. The 

 killifishes differ from both in the extremely protractile 

 premaxillary bones, a condition very easily demonstrated 

 by examining the upper jaw and prodding its edge for- 

 ward. In form the body is oblong from elongate and 

 slender to deep and nearly orbicular. The head is usually 

 large and robust, often quite chunky. The mouth is small, 

 with short gape, though wide and terminal. The teeth are 

 extremely diverse, from broadly incisor-like to finely 

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