56 BOARD OF AGRICULTURE. 
Many observers state that these worms have no mouth and 
no digestive organs whatever, but obtain their nutriment by 
absorbing the nutritive materials by which they are surrounded 
in the intestine of their host directly into their own tissues, 
after the manner of the tape-worms. M. Lespes* states, how- 
ever, that Echinorhynchus claveceps, found in the minnow, etc., 
has a complete alimentary system. The mouth is very small, in 
form of a pore, opening at the end of the proboscis and raised 
upon a small mobile papilla. This mouth communicates with 
a short digestive cavity, in the form ofa blind sac. He states 
that he has seen the refuse of the food ejected from the mouth. 
Upwards of 100 species of these worms have been described, . 
nearly all of which are referred to the genus Hchinorhynchus. 
They are especially abundant in birds and fishes. 
Those species in which the development has been studied, 
have a kind of alternate generation, the young embryo be- 
ing very different from the parent, and afterward developing 
in its interior another form, which in turn becomes like the 
grandparent. M. Lespes states that #. claveceps. produces 
“ cocoons” containing 150 to 200 eggs. The embryos devel- 
oped in the eggs are capable of moving while still in the shell, 
and remain alive fora year. On feeding a snail with food 
containing these eggs, they hatched in his intestine, and the 
free embryos were quite lively and active, and furnished with 
two pairs of hooks for boring purposes. They had consider- 
able resemblance to the free embryos of tape-worms and no 
doubt have similar habits, but they failed to masons their 
transformations in the snail. 
Leuckart fed the eggs of E. proteus, found in the trout and 
other fishes, toasmall crustacean, Gammarus pulex. The eggs 
hatched in a few days and the young embryos bored their way 
through the intestine into the general cavity of the body, some 
of them penetrating into the limbs. In the course of three 
weeks they grew larger and the granular mass still in the inte- 
rior of the body of these embryos developed into a distinct or- 
ganism, which afterwards developed a proboscis, muscles, and 
the other peculiar organs of an Echinorhynchus,becoming gradu- 
* Journal de l’ Anatomie, 1864, p. 683 ; Gunther’s Zoological Record, 1865, p- 747. 
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