PROTRACTILE MOUTHS 



which enables it to act with greater effectiveness. A 

 victim an inch or two away from the lips still closed, 

 which might escape if they opened and closed in the 

 usual way, finds itself encircled in this sudden darting 

 motion. It is snapped up and swallowed, without 

 possibility of escape. Here we find the highest degree 

 of perfection in the method of securing food by the 

 mouth. 



The John Dory, and the fish of the same family, that 

 of the Zeid<£^ so called from the generic name {Zeus) of 

 the dory itself, are not the only ones to be furnished 

 with a mechanism so specialised, extraordinary, and 

 so well adapted to its purpose. There are a few others, 

 like the sand smelts, which are related to the mullet, and 

 the Picarels, which are near relatives of the sea bream. 

 Most of them are small; they are found on the coasts 

 of nearly all seas, and belong to many genera and 

 species. The sand smelts are often found near the 

 shore in the Atlantic and the Mediterranean in the 

 summer, often in considerable shoals. Fishermen 

 catch them by the thousand. They are to be seen in 

 heaps in fish shops, where their fine and delicate hue 

 and their silvery glitter attract the eye, especially 

 the brilliant band running down the side like a stole 

 which has caused French fishermen to call them 

 " priests ". Their family, that of the Sand Smelts, has 

 species of greater size in tropical seas, and their flesh 

 retains the fine qualities of the smaller species of tem- 

 perate waters. One of these is very highly valued in 

 South America, where it has been called " Peje rey ", 

 the king-fish. 



The family of Sand Smelts or Atherinids, Menids 

 or Picarels, and Zeids, all have a protractile mouth. 

 Although they are different in other respects, they 

 resemble one another in this. All three belong to 

 distinct groups of fishes. Their nearest neighbours 

 either show no trace of this peculiarity or only in a very 

 slight degree. Other species have a semi-protractile 

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