734 



ARTHROPODA 



A succession of ecdyses results in the formation of the nymph, 

 which resembles the adult, except that it possesses numerous 

 chitinous spicules on its skin, and by the sixth to the seventh month 

 is about 6 to 8 millimetres in length. 



These nymphae now wander about the host, and are supposed to 

 reach the bronchi, and thus to leave the herbivorous host and 

 reach the dog either by the nose or mouth, in the nasal cavities of 

 which they moult and become sexually mature, copulating about 

 the sixth to seventh week after infection. 



Pathogenicity.— Both the larva and the adult may be found in 

 man, the former in the lung, rarely in the liver, spleen, or intestinal 

 wall. The latter has but rarely been met with, and then appears to 

 be due to embryos wandering into the nose and developing directly. 

 Hitherto it has only been found in man in Europe and^Central 

 America. 



Porocephalus Humboldt, i8ii. 



Linguatulida with cylindrical body and continuous coelom. 



Type Species,— Porocephalus armillatus Wyman, 1847. 



Species. — ^There are about twenty known species, of which P. 

 YMillatus and P. moniliformis are known to occur in man, and will 

 be described below, but Sambon suspects that P. crotali,P. clavatus, 

 P. stilesi, andP. najcB will probably also be found in man as scientific 

 work in parasitology extends. 



Pathogenicity, — They cause porocephalosis in man and animals. 



Porocephalus armillatus Wyman, 1847. 



Synonyms — ^Adult. — Linguatulida armillata Wyman, 1847 ; Penta- 

 stomum polyzonum Harley, 1856; Porocephalus moniliformis Neu- 

 mann, 1899, pro parte. Nymph. — Pentastonum diesingi Beneden, 

 1849; P. euryzonum Diesing, 1850; P. leonis Weddell, 1863; P. con- 

 strictuM von Siebold, 1852; P. protelis Hoyle, 1883; Linguatulida 

 constricta Kiichenmeister, 1855. 



Porocephalus with cylindrical body, slightly flattened on its 

 anterior face, and surrounded by about sixteen to twenty-two dis- 

 tinct rings, separated from one another by a wide interval. The 

 body tapers from the middle backwards. 



Remarks. — -The larva of this parasite was discovered by Pruner in 

 the liver of two negroes in Cairo in 1847, and subsequently by Bilharz, 

 Fenger, Kearney, Crawford, Marchoux, Chalmers, and others ; while 

 the adult was discovered by Wyman in 1848 in the lungs of the 

 African python. The adult was discovered by Savage in Python 

 sehcB and described by Wyman in 1845. Sambon has recently 

 studied both adult and larva. 



The adult lives in African pythons and snakes (Python seba, 

 P. regius, Bitis nasicornis, and B. arietans). The larval forms 

 usually occur in Proteles cristatus, Cynocephalus maimon, and other 

 monkeys; in Erinaceus cethiopicus, the African hedgehog; and in 

 Felis leo, the lion. 



