XXvi EXPLANATION OF THE TLATES. 



d. Fourtli stage. 

 Fig. 5. Small portion of the germinal membrane of Acephalocystis 



annates. 

 Fig. 6. Small portion, higlily magnified, of the granular matter from 



the cyst of Cysticercus. 

 Fig. 7. Small portion of the inner surface of the external membrane 



of Ace/>haIocj/stis armatus while in a state of degeneration. 

 Fig. 8. 0\iim from the pedicle of Cysticercus. 

 Fig. 9. Small portion of the germinal membrane of Acephalocystis 



monroii, highly magnified. 



a. Fibrous basis. 



b. Germinal vesicles. 



c. Secondary' aceiDhalocysts -svithin the germinal vesicles ; this 

 portion was taken from the large parent cyst, which is the 

 primary animal, buried in the liver ; and each of the smaller 

 vesicles marked c belong therefore to the secondary genera- 

 tion, their progeny again being the tertiary generation. 



Fig. 10 Is a specimen of Cysticercus negUcliis ruptured at the fundus of 

 the sac, apparently for the escape of the yoimg germs into 

 the cavity of the cyst, where thej^ become attached. 



Fig. 11. Small portion of the cyst of Cysticercus neglectus magnified, 

 sho\^•ing its vascidarity, and the mode of attachment of the 

 young Cysticerci to its internal siuface. 



Fig. 12. View from above the pedicle of Cysticercus, showing the dis- 

 position of the teeth. In all works hitherto published on 

 Helminthology, there has been a great want of proper figures 

 or descriptions of the tnie generic and specific characters of 

 these animals, a point of the utmost importance for obtaixung 

 a proper knowledge of them : with this ^dew the author has 

 paid scrupidous attention to the leading characters, and these 

 he has placed in the form of a synopsis at the end of the 

 chapter. All the drawings have been made «-ith the view of 

 illustrating these characters more fidly. The disposition of 

 the teeth, and their forms, are perhaps the most certain ex- 

 ternal characters. 



Plate XI. page 482. 



Fig. 4. Magnified view of a small portion of tlie external or tubular 

 membrane of Diskostoma acejjhalocystis. 

 a. Larger disc. 

 h. Smaller one on its surface. 



c. Tubvdi. 



d. Extremities of tubes. 



e e. Gemmules, which at this stage of development may act as 

 absorbents. 

 Fig. 5. Natural size of Diskostoma acephalocystis. 

 Fig. 6. Diskostoma acephalocrjstis in various stages of development. 



