LIXGUATULIDA 



4S9 



testine and reach the liver. There they surround themselves with 

 a cyst, in which they pass through a series of changes of form, ac- 

 companied, as in insect larva 1 , by repeated ecdyses (fig. 378). When 

 six months have elapsed, they have attained a considerable size 

 and have acquired the four oral hooks, as well as a number of finely 

 serrated superficial rings. They have now reached the stage formerly 

 described as P. denticulatum (fig. 377), in which they break through 

 their capsules and begin a fresh migration. They traverse the liver, 

 and if present in great numbers, occasion the death of their host. 

 In other cases, on the other hand, they soon become enveloped in 



. 379. Ripe male of Atax Sonzi, seen from the dorsal surface (after E. Claparede). El, 

 Pedipalpus ; G, brain ; Oc, eyes ; T. testis ; N, Y-ahaped gland ; D, intestine ; A, 

 anus ; lid , cutaneous glands. 



another cyst. If they now pass with the flesh of the Hare or 

 Rabbit into the buccal cavity of the Dog, they penetrate into the 

 neighbouring air-chambers, and in two or three months become 

 sexually mature. 



Pentastomum t&nioides Rutl., 80-85 mm., Male only 18-20 mm. long. P. 

 multicinctum Harl., in the liver of Naja liajc. P. constrictum v. Sieb. Encysted 

 in the liver of negroes in Egypt. 



Order 2. ACARINA,* MITES. 



Aruchnida with stout body. The abdomen is unsegmented and 

 * 0. Fr. Miiller, " Hydrachnre," etc., 1781. A. Duges, " Recherches sur 



