$ 115. THE HELMINTHES. 123 
Taenia, it is a reservoir, composed of numerous ramified coeca, and inti- 
mately blended with the parenchyma of the body.» The vagina is a nar- 
row, muscular canal, which usually opens close to the penis by a special 
orifice (Vulva), or by a common genital opening (Porus genitalis). 
It is difficult to decide whether the testicles, which always form the 
middle layer of the body, consist of a collection of inter-opening caeca, or 
of a single spirally-rolled tube. The cirrhus-sac with the Vas deferens open- 
ing at its bottom, is always very distinct. As in the Trematodes, it has a 
Vesicula seminalis, with a Ductus ejaculatorius and a muscular penis. 
The contents of the different canals, the seminal vesicle and the ejacula- 
tory duct, are always very active, filiform spermatic particles.” The 
. genital openings are upon the middle of the ventral surface, or on the 
lateral borders of the body ; but in those species where the sexual openings 
are separate, they are lateral for the male, and ventral for the female. 
The eggs of the Cestodes, situated like those of the Trematodes in a 
spiral, pouch-like uterus, have also a similar structure. Their simple, oval, 
brownish-yellow envelope, has also, sometimes, an operculum. The eggs 
of Taenia have a very different structure ; the envelope is colorless, and 
of a very variable, and sometimes quite remarkable form.” 
23 With most T'aeniae the borders of the cellular 
uterus are very difficult to distinguish. But its 
lateral caeca with Taenia ocellata, and its arbo- 
rescent divisions with Taenia solium, are very 
easily seen; see Delle Chiaje, Compendio di 
Elmintografia umana, Tav. ILI. fig. 10. 
2% The cirrhas-sac is either short and pyriform, 
or very long. With very many T'aeniae, as with 
Taenia amphitrica, lanceolata, multistriata, 
scolecina, and setigera, the penis has numerous 
small spines pointing backwards; see Dujardin, 
Ilist. d. Helm. Pl. IX.-XI. That of T'aenia 
infundibuliformis is surrounded with very large 
bristles ; and according to Dujardin (loc. cit. Pl. 
IX. B. 210) this is also true with Taenia sinuosa. 
25 By very slight pressure, the spermatic parti- 
oles contained in the Vesicula seminatlis of the 
cirrhus-sac are pressed out through the penis ; 
this is so with Bothriocephalus punctatus, latus, 
Taenia cucumerina, planiceps (from the intes- 
tine of Hirundo urbica), inflata , pectinata, ser- 
pentulus, and villosus. As with the Trematodes, 
the spermatic particles here cease to move when 
put in water, and are twisted into loops.* 
2% With Ligula, Bothriocephalus nodosus, 
latus, claviceps, ditremus, punctatus, and te- 
gilis, proboscideus, rugosus, and with most Tae- 
niae, the cirrhus-sac and the vagina open by a 
common genital orifice upon the lateral border, 
and usually through a papilla. With Taenia 
cucumerina, and bifaria, mihi-(from the intestine 
ot Anas leucophthaimus), I have found an orifice 
of this kind upon the two lateral borders of each 
segment, and behind which were the genital or- 
gans.t 
27 Although I have not seen either the germina- 
tive vesicle or dot in the eggs of the Cestodes, 
probably from their delicacy, yet I do not fora 
moment doubt their presence there, since Kélliker 
(Muller’s Arch. 1848, p. 92, Taf. VII. fig. 44) has- 
seen them in the eggs of a Bothriocephalus. 
Many species of this genus produce oval eggs 
which have a simple brown envelope. Of an oval 
form, but colorless, are those of Caryophyllaeus, 
Ligula, Triaenophorus, Taenia literata, and 
scolecina. Those of Taenia amphitricha, bifa- 
ria, macrorhyncha, serpentulus, and serrata, are 
round, and have two colorless envelopes ; this is true 
also of the oval eggs of T'aenia angulata, villosa, 
&c. There are three of these envelopes with the 
round or oval eggs of Bothriocephalus infundibul- 
tformis, proboscideus, Taenia porosa, lanceo- 
trapterus, the two genital op gS are ted 
on each side of the ventral surface, while the penis 
protrudes from a special opening directly in front 
of the vulva; see Mehdis in Isis, 1831, Taf. 1. fig. 
1, 2, and Eschricht, loc. cit. Tab. I. fig. 5. 
With Bothriocephalus punctatus, there are 
two pairs of these openings upon each segment, 
one under the other, but in Bothriocephalus te- 
trapterus, these are side by side. With Triaeno- 
phorus, nodulosus,and Taenia ocellata, the vulva 
is upon the ventral surface, and the penis upon 
the lateral border. With Bothriocephalus fra- 
* [§ 115, note 25.] I have observed the de- 
velopment of the spermatic particles with Taenia. 
They are developed in special cells, and before 
they have escaped,are therein coiled up resembling 
those of the coleopterous insects. They are simply 
filiform. — Ep. 
t [§ 115, note 26.] The Cestodes have been the 
objects of much careful study during the last few 
lata, llata, setigera, and solium. With Tae- 
nia infundibuliformis, and planiceps, each ex- 
tremity of the envelope is lengthened into a long 
and delicate appendage. Two similar but fibril- 
lated appendages exist upon those of Taenia 
variabilis. With Taenia cyathiformis, the ex- 
ternal pyriform envelope of the-eggs has, at its 
attenuated extremity, two round, bladder-like ap- 
pendages. Dujardin (Hist. d. Helm. Pl. IX.~ 
XII.) and I (Burdach’s Physiol. 1837, II. p. 201) 
have seen many other forms with the eggs ot 
Taenia. The round and doubly-enveloped eggs 
years, by Blanchard (Ann. d. Sc. Nat. X. 1848, 
p. 821) and Van Beneden (Mem. Acad. Belgique, 
1850, XXV.) and the sexual parts pretty clearly 
made out. They both agree that, internally, the 
male and female organs are wholly distinct, and 
therefore that impregnation of the ova must be by 
self-copulation. — Ep. 
