Excerpta Zoologica : Metamorphoses of Intestinal Worms* 119 



in the muscles of the latter mostly singly, sometimes several lying 

 together in nests, and inclosed in a common pseudo-membranous cyst. 

 I (adds Dr. Siebold) am somewhat surprised at the latter part of this 

 statement, as I have never met with more than one individual of Fit. 

 piscium inclosed in a cyst in Gadus Callarias. (Wiegmann's ■ Archiv,' 

 vol. i. p. 306, 1838.) Miescher's description of the worm agrees 

 with the one I have there given, with the exception that Miescher 

 does not notice the peculiar band-like organ, which, according to my 

 own researches, extends through the entire cavity of the body of the 

 Filaria ; on the other hand, Miescher succeeded, in the further course 

 of his inquiries, in detecting the sexual parts, which at first appeared 

 to be entirely missing. He found the female sexual organs arranged 

 in the usual manner, but so minute and delicate that they were easily 

 overlooked. The two oviducts even in the largest specimens did not 

 contain any trace of eggs, but their contents seemed to consist 

 merely of a limpid fluid mixed with a few very minute granules. 

 The sheath reached the muscular membrane at the end of the first 

 third of the worm, but no external aperture could be perceived. 

 These Filaria seem to be subject to a changing of skin, as Miescher 

 not only met with a number of shrivelled empty sacs, but frequently 

 found Filaria still situated in these sacs and crawling about with 

 them ; such a sac surrounded accurately the body of the Filaria, but 

 projected somewhat beyond trTe anterior and hind part of the worm, 

 and contained in its cavity a clear fluid, sometimes rendered opake 

 *by granules. 



In company with these Filaria, Miescher always found, in consi- 

 derable number, peculiar chrysaloid bodies, but stiff and without 

 motion, lying free in the ventral cavity, or buried in the muscles of 

 the ventral walls ; sometimes they lay in one and the same fold, 

 and were inclosed by similar pseudo-membranous cysts. These 

 chrysaloid bodies consist of two parts, of a globular or ovate body 

 (resembling in form a Florence oil-flask), and of a cylindrical tail 

 proceeding from it. The head is about § to | lin. in diameter and 

 1 to J in length, and is drawn out at its free end into a short trun- 

 cate umbilicus. The tail is from 4 to 6 lines long, separated by 

 a distinct constriction from the head, rounded at its extremity, 

 and generally curved in the form of a crozier. I conceive these 

 chrysaloid bodies to be perfectly identical with those described and 

 figured by Leblond (Ann. des Sciences Nat., 1836, p. 290. pi. 16. 

 fig. 2, 3.), from Murana Conger. With regard to the changes which 

 these bodies gradually undergo, Miescher observed that the tail not 

 only decreased in length but entirely shrivelled up, so that at last 

 only the head remained ; in the mean time this expanded into double 

 or thrice its volume, and appeared at last as a simple elongate rounded 

 sac. This sac, whether it still possessed a caudal extremity or not, 

 always consisted of an external thicker brownish- coloured covering, 

 beneath which was a second always more delicate, transparent cover- 

 ing, inclosing a cavity corresponding to the external form of the sac ; 

 this cavity was quite filled by a new worm, the form of which was 

 according to that of the cavity ; so long, for instance, as the chry- 

 saloid body still consisted of head and tail, the more or less pro- 



