748 
ZOOLOGICAL LITERATURE. 
proper cavity, and containing cells differing from those of the intestinal epi- 
thelium in their smaller size and in containing a large ti-ansparent nucleus. 
The smaller the individuals, the easier was it both to see and to isolate the 
alimentary system. The female sexual organs have long been known as peculiar. 
The origin of the floating ovaries, or egg-masses, has long been doubtful j and 
an examination of nearly a thousand specimens of JEch. clavceeeps did not 
satisfy the author as to the views of either Dujardin or Von Siebold^ but an 
examination of Ech. proteus, also parasitic in the minno'sy, demonstrated the 
perfect accuracy of the opinion of Siebold and the recent researches of Pagen- 
stecher on this point, viz. that it is most certainly in the liganientum suspen- 
sorium that the egg-masses take their origin, and at a point corresponding to 
where in the males the testes are found. At the pavilion a muscular tube 
arises which opens at the posterior extremity of the body j it presents two 
glandular bodies, one above the pavilion, another at the inferior opening ; the 
latter is generally of a yellow colour and plays an important part, as it secrets 
the cocoon for the eggs. These eggs are not laid singly, but in spherical 
cocoons containing from 150 to 200 ova. The cocoons can sometimes be found 
suspended to the extremity of the body of the female j the cocoons become 
free in the intestine of the fish, soon become broken up, and the ova escape. 
The embryo forms of Echinorhynclms have been investigated by Siebold and, 
more recently, by Guido Wagner. The embryo of Ech. clava:ceps is remark- 
able for the complete absence of all hooks, not only from its body but also 
from its head. The embryos are immoveable in the egg, and in this condition 
the author has kept some alive for more than a year. By feeding some snails 
on flour mixed with the ova of the Ech. yiyas, the hatching of the embryo 
was observed. It first of all ruptures the internal membrane, not the outer 
covering (coquille), when it is free in the intestine of the snail. It then so 
remarkably changes its form, that had the author not watched it hatching he 
would have hesitated to recognize it. The mouth-opening is terminal. Two 
pairs of large hoolis, at first recumbent, are elevated and diverge j the entire 
animal is elongate and takes the form of a club. At this stage it executes most 
rapid and wonderful movements : advancing its head with the hooks diverging, 
it supports itself on them and withdraws the rest of its body. From these move- 
ments and their great resemblance to some of the cestoid embryos there 
would be little doubt but their ultimate destination was to traverse the tis- 
sues of animals. Once M. Lespes foimd one in the liver of a snail. At this 
stage in their existence his experiments came to an end : as to what ultimately 
became of them he was unable to determine j and this perhaps was in some 
measure due to the artificial means taken to hatch the eggsj for it is pretty cer- 
tain that they are not generally developed in the Mollusca, and after the lapse 
of a few days not an embryo would be found in the snaiPs intestine, they having 
all made their escape with the excreta. lie tried to watch the hatching of 
Ech. clavccceps by feeding some of the common species of Limncci with them ; 
but though he has seen them at different stages of their hatching, he never 
witnessed any such remarkable movements as in the case of those of Ech. 
yiejas. To see the larvo3 in a living state, the best plan is to mix the pel- 
lets of a snail fed on the ova, passed one or two days after the ova have been 
given, with some sugar and water ; plain water kills them and rapidly changes 
their form. 
On Greeff’s researches into the anatomy of Echinorhynchus, especially 
E. milianusj see p. 741, 
