$$ 114, 115. THE HELMINTHES. 119 
CHAPTER IX. 
ORGANS OF GENERATION. 
§ 114. 
Although most of the Helminthes propagate by means of genital organs, 
yet there are a few species which multiply by fisswration and gemmation. 
The fissuration is always transverse, and differs from that of the Proto- 
zoa and Zoophytes in the fact that complete individuals are not produced, 
there being only a separation of certain organs from the perfect animal, as, 
for instance that of the segments of the body in the Cestodes. This fissu- 
ration is complete or incomplete. In the first case, occurring in the Taenia, 
the segments are detached from the body, and continue to live independ- 
ently, without, however, ever forming a new individual.” 
Gremmation has been observed in the sexless Coenurus and Echinococcus. 
In Coenurus cerebralis, it is incomplete. The buds are formed on the 
internal surface of the parent-vesicle, and never separate from it, nor 
become perfect individuals. They have only a head and neck which pro- 
ject outwardly after the complete development. In Echinococcus, however, 
the gemmation is complete. The buds appear as in Coenurus, but the 
young animals are sooner or later detached and fall into the liquid of the 
parent vesicle. -When completely developed, this vesicle bursts, and they 
are set at liberty. That their development occurs in this way is shown by 
their hanging by a cord, which, like the tail of Cercaria, is inserted into a 
fossa at the posterior extremity of the body. Like this last, also, this cord 
subsequently disappears, and the young animal moves freely about, by the 
aid of its double circle of hooks and its four suckers. 
§ 1165. 
Tn those species which reproduce by male and female genital organs, these 
last are sometimes upon a single animal, and sometimes upon two separate 
individuals. The eggs and spermatic particles are formed after very differ- 
ent types. In all, the copulatory organs are extraordinarily developed. 
The Cestodes and Trematodes are hermaphrodites.” The structure of 
1 The imperfect fissuration with Ligula and 
Triaenophorus is limited almost to a constriction 
of the lateral borders. With Bothriocephalus 
punctatus, it is only here and there that a ring is 
detached, and over most of the body the transverse 
and opposite sulcations do not extend near to the 
median line. With Bothriocephalus tetrapterus, 
the fissuration is more complete ; but even here, 
there are only some incompletely limited rings 
among numerous others which are completely so. 
Of all Helminthes the J'aeniae have the most 
complete fissuration ; here not only is the separa- 
tion of the rings indicated by a complete furrow, 
but the rings are sometimes detached and live thus 
independently. The separated rings of Taenia 
solium, cucumerina, and others, move freely, and 
are vo individualized, that they resemble some 
Trematodes. 
2See Chemnitz, De Hydatibus Echinococci 
hominis commentatio, 1834 ; Muller, in his Arch. 
1836, p. CVII. ; and Siebold, in Burdach’s Phys- 
iol. II. 1837, p. 183. 
1 According to Nordmann (Microgr. Beitr. Hft. 
2, p. 141), Diesing (Ann. d. Wiener Mus. I. 
Abth. 1, p. 9), and Miram (Nov. Act. Acad. 
XVII. pt. 2, p. 636), the male and female genital 
organs of the genus Pentastomum, classed by 
many modern Helminthologists among the Trema- 
todes, are situated upon different individuals. But. 
Owen affirms to have observed the opposite 
(Trans. of the Zool. Soc. of London, 1835, I. p 
325). The only way to settle this point is by 
analyzing accurately the contents of these organs ; 
a method pursued by Valentin (Repertorium II 
1837, p. 185), who found filamentoid spermatic 
particles in the organs of an apparently female 
