206 



PARASITES OF THE DOMESTIC ANIMALS 



white, irregularly grouped spots, each representing an invaginated larval 

 tapeworm head. These vary in degree of development and in number 

 from four hundred to five hundred, and herein lies an essential differ- 

 ence between coenurus and cysticercus, the latter containing but^one 



Fig. 114. — Diagrammatic section of Ccenurus: a, normal dis- 

 position of soolex ; b, u, d, e, diagrammatic representation to show 

 the homology between cysticercus and coenurus (after Ransom, 

 from Railliet, Bull. No. 66, Bureau An. Ind., TJ. S. Dept. Agr.). 



Fig. 115. — Brain of lamb, showing the furrows pro- 

 duced by the migration of the young gid bladderworms, 

 taken at a time immediately following the period of 

 invasion — i. e., from fourteen to thirty-eight days after 

 infestation, — natural size (after Ransom, from Leuck- 

 art. Bull. No. 66, Bureau An. Ind., U. S. Dept. Agr.). 



Fig. 116. — Gid bladderworm 

 showing immature tapeworm 

 heads, — natural size (after 

 Ransom, from Railliet, Bull. 

 No. 66, Bureau An. Ind., U. S. 

 Dept. Agr.). 



head. In some cases the heads may be found evaginated to the surface 

 of the vesicle (Davaine), when the cerebral disturbance by pressure is 

 contributed to by the direct irritation from the booklets. 



Development. — ^Animals susceptible to gid become infested by eggs 

 of the tapeworm Multiceps multiceps which is harbored by dogs. The 

 eggs and gravid segments, spread about as they are, will, in the presence 



