Dr. Baird on Entozoa, or Intestinal Worms. 151 



time after having swallowed them, and the progress of the En- 

 tozoon traced to maturity. The Ccenurus cerebralis, too, which 

 I have particularly mentioned as being the cause of the " sturdy" 

 in the sheep, has been asserted by this acute observer to be like- 

 wise the young of a species of Tsenia, or tape-worm ; though his 

 observations upon that head have not been sufficiently matured 

 to determine the species into which it is transformed. Should 

 these observations be proved to be correct, it is impossible to 

 say of what immense value this knowledge may become ; and 

 M. Siebold believes that he will soon be able to point out to 

 farmers the means of preventing the development of these para- 

 sites, the presence of which in sheep, &c, is known to exercise 

 such a fatal influence*. 



Annexed is a list of the Entozoa as yet known to me to have 

 been noticed occurring within the limits of the Club. In giving 

 the name of the species, I have referred to the lately published 

 Catalogue of the Entozoa in the collection of the British Mu- 

 seum, for its synonyms, and have in addition given a reference 

 to where it is described by Rudolphi or Dujardin. With one 

 exception, all the species here mentioned have been communi- 

 cated by our Secretary, Dr. Johnston : — 



* M. Siebold believes that the ova of the Taeniae of certain carnivorous 

 animals are occasionally introduced into the bodies of sheep and other 

 Ruminantia ; that in them they assume a vesicular form, instead of be- 

 coming developed into true tape-worms ; but that this change takes place 

 as soon as the proper habitation is secured for them. The possibility of 

 the ova of the Taeniae of animals of one order, as for instance the dog, be- 

 coming conveyed into the stomach of those of a different order, such as 

 the sheep, &c, derives confirmation from a fact which has come under my 

 own observation, viz. that it is common for dogs to discharge from their 

 bowels separate detached joints or articulations of tape-worms in great 

 quantities. Some months ago, a considerable number of these detached 

 articulations, which were found adhering to the hinder parts of a favourite 

 pet dog, were forwarded to the British Museum ; and it is a curious cir- 

 cumstance, that since this paper was written, another instance of the same 

 thing has occurred to one of the members of this Club. Several detached 

 joints of a Taenia have very recently been forwarded to me by our Secretary 

 for examination, with the information that they came from a pet dog be- 

 longing to Mr. Clark of Belford Hall. The species of tape-worm is the 

 Tcenia cucumerina. Now it is very possible that the articulations con- 

 taining (as we know they do at times contain) mature ova. may be ejected 

 by the dog on the moist grass in the fields, and from thence conveyed 

 along with the food into the stomach of the sheep grazing in the meadow ; 

 there to take on an encysted form, and assume the character which suits 

 their new habitation. 



