Comparative anatomy / by C.Th. v. Siebold and H. Stannius ; translated from the German, and edited with notes and additions recording the recent progress of the science by Waldo I. Burnett.

  • Karl Theodor Ernst von Siebold
Date:
1854
Catalogue details

Licence: Public Domain Mark

Credit: Comparative anatomy / by C.Th. v. Siebold and H. Stannius ; translated from the German, and edited with notes and additions recording the recent progress of the science by Waldo I. Burnett. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

    120/482 (page 116)
    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. Its canals have proper walls, the contraction of which pro- duces the circulation. 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 the whole body; and in which are 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 Wiesmann's Arch. 1838,1. 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.t 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- rum b and Burovu 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 R£gne animal, nouv. Edit. Zoophytes, PI. XXXV. fig. 2. —Ed. a contractile net-work spread over two larger trunks, which pass along Platner (Muller's Arch. 1838, p. 572, Taf. XIII. 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 Taenia, 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- riocephalus 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 Diplostomum (Nordmann Microgr. Beitr. lift. 1, Taf. II. 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 ; 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 as t [§ 110, note 6.] Berthold (Heber den Bau des Wasserkalbes. &c. loc. cit.) has described a vascular system with the Gordiacei; but Blanchard (Ann. d. Sc. Nat. 1849, XII. p. 7) has failed to confirm his statements after very careful research. — Ed.