LIXliUATULIDA ACABINA. 



testine and reach the liver. There the}' surround themselves with 

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

 companied, as in insect larvae, 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. The}' 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 Ata.r Sun:!, seen from the dorsal surface (after E. Claparede). Kf, 

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

 anus ; Sd, cutaneous gland*. 



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. 



ttrnioiilfx Hud.. 8n-S.~> mm.. Male only 18-20 mm. long. P. 

 ini/ffli-hu-fi/nt Harl., in the liver of X<ijn fn/jr. P. rnnxfrii-f-inn v. Sieb. Encysted 

 in the liver of negroes in Egypt. 



Order 2. ACARIXA,* MITES. 



Arachnida with utm/i hod//. TJie abdomen is unseymented and 

 * 0. Fr. Muller. " Hydrachnje." etc., 1781. A. Duges, ' Eecherches sui' 



