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LI. On a Double-bodied Intestinal Worm^ the Syngamiis 

 trachealis. By Dr. Charles Theodore von Siebold, 

 of Danzig.^ 



THIS remarkable parasitic animal, which I will here de- 

 scribe, was discovered about twenty-five years ago, but 

 its internal structure was imperfectly known, and the attention 

 was not paid to it which it merited. At the present time it ap- 

 pears to be quite forgotten, and I therefore present it again 

 to the friends of helminthology with its true structure and 

 with a new name ; perhaps I shall be able to procure for it a 

 determinate place in the system f. 



The worm of which I speak must, according to its struc- 

 ture, be classed with natural monsters, and may justly be 

 placed by the side of Diplozoon paradoocum. The Diplozoon 

 paradoxum % can no longer be considered as the only known 

 double animal, for our Syngamus trachealis is also one, but with 

 this difference, that it does not consist of two hermaphrodite 

 animals closely connected together, but that a male am] Jemale 

 animal are grown together. 



Before I begin the description of this monster I will state 

 what is already known of it. Montagu described this worm 

 as a Fasciolak, and has given an indifferent drawing of it ||, and 

 mentions as its habitat, the trachea of young hens, pheasants, 

 and partridges. He found twenty such worms in one wind- 

 pipe. Montagu ascribed to it a disease known in England by 

 the name of gapes, which often seizes the young poultry a short 



• From Dr. Ar. Fr. Aug. Wiegmann's Archivfur Naturgeschichtej Part 11, 

 1836, p. 1 05. Translated by W. Francis. 



[t Since the publication of this paper, a memoir by Nathusius, inserted in 

 the first number of Wiegmann's Archiv for 1837, proves the Syn. trachealis 

 of Siebold to be a species of Strongylus in the act of coitus. A translation 

 of this paper will appear in a future number of our Journal. —Edit.] 



X I here take the opportunity of adding to the observation which has 

 been made on the circulation of the blood in the Diplozoon, (see Nordman's 

 jB«<mge,p.69, and myfirst paper in Wiegmann's ^rcAiu, Partl.,1835, p.58.), 

 the following correction. New observations which I have made on this animal 

 since the ciliary motion of Purkinje was made known, have convinced me 

 that the motion of the blood is not perceived in the vascular system of this 

 animal, but that the movement arises from the inner surface of the vascular 

 membrane, as Ehrenberg has lately stated in Wiegmann's Archiv^ Part II. 

 p. 128. The vessels possess on the inner surfaces moving cilia, which 

 exactly imitate the motion of the blood. This movement resembles the ci- 

 liary motion described by Henle (MUller's Archiv'^W. 6, p. 576.) in the tor- 

 tuous canals of the Branchiobdella parasita^ and which I also have seen in 

 this animal. 



§ Account of a species of Fasciola, which infests the trachea of poultry, 

 with a mode of cure, by George Montagu, in the Memoirs of the Wernerian 

 Natural History Society, vol. i. for the years 1808, 9, 10. Edinb.Svo, p. 194. 



II Ibid. Pl.vii.fig.4, 



