Some Features of Ornamentation in the Killifishes or Toothed Minnows

Abstract

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 sections 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 (Cyprinidm), 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 pikelike fishes (Haplomi). Such are all internal and largely have reference to the bony skeleton. In the abdominal ventral fins (Procato puts excepted), and without true spines in the dorsal and anal fins, the order resembles the herring-like fishes (Isospondyli), but differs in the absence of a mesacoracoid bone. This latter character is in agreement with the host of spiny-rayed fishes (Acantlhopteri), but they usually have the ventral fins well anterior. Though six families are included in the order of pikelike fishes, only the mud-minnows (Umbridm) and the pikes (Esocidm) 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 forward. 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