THE CYPRINODONTS. 
Tue “ Cyprinodonts,” “ Top minnows,” or “ Toothed Carps,” as they are 
variously called, form a well defined group. An average of their shapes 
would approach that of a common Gold Carp with the tail rounded instead 
of notched. The species resemble the Carps, Cyprinidw, in form, possession 
of a single dorsal fin, absence of a pouch on the stomach, lack of pyloric ap- 
pendages, and in other features; but they are readily distinguished by scales 
on the head, and the teeth on the jaws, by the forms and dentition of the pha- 
ryngeals, the structure of the air bladder, and by their habits. In a general 
way it may be said of this family they are surface fishes, while the Carps, 
properly so designated, are fishes of the bottom. All the Cyprinodonts are 
small; none of them reach the length of a foot, most are less than six 
inches; and among them are found the smallest of the fishes, in species 
of which the individuals are fully mature at a length of less than an inch. 
From carnivorous they range to mud-eating, and from oviparous, laying 
numerous eggs, to ovoviviparous, producing comparatively few. Like other 
bony fishes some lay their eggs; others ‘retain the embryo until the yolk 
is entirely absorbed; in a few of those that keep the embryo until fully 
developed, it is provided with albuminous nutriment, in addition to the 
yolk, within the egg, and is possessed of a peculiar temporary absorption 
system by which it avails itself of the provision. From ordinary sexual 
habits, such as most prevail among their allies, the Cyprinodonts vary to 
the extraordinary conditions, described below, in which the males and 
females are rights and lefts, that is, in which a dextral male pairs with 
a sinistral female, or a sinistral male with a dextral female. In this case 
sexes exist in nature that in a measure are 
‘ Like those sweet birds that fly together, 
With feather always touching feather, 
Linked by a hook and eye,” 
of the poet’s imagination.* 
* Translated by Moore from Abdallah’s Persian, referring to the jaftak, ‘‘a sort of bird that is said to 
have bat one wing; on the opposite side to which the male has a hook and the female a ring, so that when 
they fly they are fastened together.” 
