116 THE HELMINTHES. $ 111. 
the peristaltic actions of the body and the alternate retraction and pro- 
traction of the proboscis. 
In the Gordiacei, and Nematodes, no vascular system has as yet been 
found. Only in a group of species described as Filaria piscium, has there 
been found a riband-like organ concealed in the cavity of the body, and 
traversed by a net-work of canals, which resemble those of the lemnisci of 
the Acanthocephali. 
§ 111. 
In the Cystici, Cestodes, and Trematodes, the vascular system is well 
developed. 
duces the circulation. 
Its canals have proper walls, the contraction of which pro- 
In the first two orders, it consists of two pairs of 
longitudinal canals, which pass along the sides of the body and head, and 
intercommunicate occasionally, by transverse canals. 
These four vessels 
open, in the head, into an annular ring which surrounds the proboscideal 
sheath; there is here, therefore, a completely isolated system.” 
In the 
Trematodes, this system consists of a contractile net-work spread over 
the whole body; and in which are two larger trunks, which pass along 
the sides of the neck and body. 
5 Mehlis (Isis, 1831, p. 82) affirms to have seen 
on the neck of Echinorhynchus gigas two small 
orifices by which the lemnisci open outwards. - But 
I have been unable to see them in this species, or 
others of this same genus. If they really exist, 
they will shed light upon the doubtful functions of 
these organs. From what we know of their struc- 
ture, it is not improbable that they belong to the 
nutritive system, and transude a liquid which 
bathes and nourishes the organs in the cavity of 
the body.* 
6 With the Nematodes, the liquid appears to 
transude through the walls of the intestine into the 
cavity of the body, and there bathe, without a vas- 
cular system, all the organs. The riband-like organ 
found in the Filaria piscium (see Wiegmann’s 
Arch. 1838, I. p. 310), and which I have also found 
in Ascaris osculata, has the same vascular rami- 
fications as the lemnisci of Echinorhynchus gi- 
gas, and the vesicle-like bodies are not wanting 
upon the course of the principal canal. Perhaps 
they also transude the nutritive liquid, for I have 
not found any communication between them and 
the intestinal canal. 
The two lateral enlargements also, which, as 
already mentioned (§ 102), are extended between 
the longitudinal muscles of the skin, have often 
been regarded as sanguineous vessels ; but I have 
observed with them neither longitudinal nor lateral 
canals. 
1 These lateral vessels, regarded by some Hel- 
minthologists as intestinal tubes, give off in their 
course no lateral branches, except these transverse 
canals. With the articulated Cestodes, these last 
are always situated at the posterior extremity of 
the articulations, thus giving a ladder-like aspect 
to the entire vascular system. They are also 
found, however, in Caryophyllaeus mutabilis, 
which is not articulated. 
* [§ 110, note 5.) The observations of West- 
rumb and Burow on the circulatory system of the 
Acanthocephali, have recently been thoroughly 
verified by Blanchard, who has illustrated it with 
excellent figures ; see Ann. d. Sc. Nat. 1849, XII. 
p. 21, and Régne animal, nouy, Eait. Zoophytes, 
Pl. XXXYV. fig. 2.— Ep. 
Platner (Miller’s Arch. 1838, p. 572, Taf. 
XIIL..fig. 4, 5) affirms to have seen semilunar valves. 
at the orifices of the transverse canals of Taenia 
solium. 
The four lateral cervical vessels which I have 
observed not only in T'aenia, but also in Bothrio- 
cephalus, and Cysticercus, may be traced with 
perfect distinctness in Taenia cyathiformis, and 
serrata, to the vascular ring which surrounds the 
proboscideal sheath. With Caryophyllaeus mu- 
tabilis, and Taenia ocellata, which are without a 
proboscis, this vascular ring does not exist any 
more than with Bothriocephalus ; here also the 
four lateral vessels widely ramify in the head, and 
form by anastomoses, a distinct net-work. Both- 
riocephtius claviceps has a similar organization. 
It should, moreover, be here observed that from 
the contraction of its very thin walls the vascular 
system will easily elude the observer. 
2 The vessels of the Trematodes are remarkable 
for their prominent flexures ; see Distomum cir- 
rigerum, tereticolle, duplicatum, and the various 
species of Diplosti Word Microgr. 
Beitr. Uft.1, Taf. Tl. fig. 8, IV. fig. 5, 6). One 
should not confound with the sanguineous vessels, 
as has often been done, the very finely-ramified 
canals of the excretory organ, which will hereafter 
be mentioned. Thus I think that the vascular 
net-work of Distomum hepaticum described by 
Bojanus (Isis,1820, p. 305, Taf. IV.) belongs to 
this excretory organ. Laurer also (de Amphis- 
tomo conico. p. 10, fig. 22), has not carefully dis- 
tinguished them 5 and Nordmann appears to have 
fallen into the same error (loc. cit.). 
_ With Diplostomum, the vessels open each side 
into a large reservoir situated at the extremity of 
the body. Between these two receptacles, the 
excretory organ passes to the extremity of the 
body, and Nordmann has taken its orifice ag 
+ [§ 110, note 6.] Berthold (Ueber den Baw 
des Wasserkalbes. &c. loc. cit.) has described a 
vascular system with the Gordiacei; but Blanchard 
(Ann. d. Sc. Nat. 1849, XI. p. 7) has failed to- 
confirm his statements after very careful research. 
— Eb. 
