526 THE ANIMAL PARASITES OF MAN 



the same larvae which are free in the oral cavity when the food is 

 being eaten migrate into the nasal cavities. After being stationary 

 a fresh skin is formed and the spine-bearing cuticula are thrown off. 

 The male attains its full size in the fourth, and the female in the sixth 

 month. The duration of life is stated to be from fifteen months to 

 several years. 



L. rhinaria has been observed in man in the adult as well as in the larval 

 condition (Pentastoma denticulatutri). Zenker first called attention to the occurrence 

 of the iarva in man, having found it nine times in the liver in 168 autopsies. Heschl 

 found it twice in Vienna in twenty autopsies, Virchow found it in Wiirzburg and Berlin, 

 Wagner in Leipzig (10 per cent.), and Frerichs in Breslau five times in forty-seven 

 autopsies. The parasite is much less frequent in Switzerland. According to Klebs, 

 one case occurs in 900 autopsies, and according to Zaeslin two cases occurred in Basle 

 to 1,914 autopsies. In the Seamen's Hospital in K\'Q\\s\.a.&\.P.denticulatum has been 

 found six times in 659 autopsies. It was almost always the liver that contained one 

 or a few specimens. The parasite was very rarely found in the kidney or spleen, or 

 encysted in the intestinal wall. The adult L. rhinaria is far more rarely observed 

 in man. 



A case reported by Landon that related to a blacksmith of Elbing is particularly 

 interesting. This man accompanied the campaign of 1870; he soon, however, fell 

 ill with pains in the liver, accompanied by icterus and intestinal disorders. Soon 

 after the war, and after the symptoms were reduced to icterus and weakness, bleed- 

 ing of the nose set in and continued with slight intermissions for seven years ; an 

 unpleasant sensation of pressure in the left nasal cavity set in, with inflammatory 

 swelling of the mucous membrane. At last, in the summer of 1878, when the 

 pressure in the nose had considerably increased, a Linguatula was expelled from the 

 nose with a violent attack of sneezing, and lived for three days longer in water. The 

 bleeding of the nose then ceased and the patient soon recovered. There can be no 

 doubt that the first illness was connected with the invasion in the liver of numerous 

 larvae of Pentastoma, and disappeared after their encystment ; one or a few of these 

 must subsequently have found its way to the nose and settled there. 



Genus. Porocephalus. 

 Porocephalus constrictus, v. Siebold, 1852. 



- Syn. : Nematoideum houiinis^ Diesing, 1851 ; Pentastonmni constrictum, 

 v. Sieb., 1852 ; Porocephalus constrictus, Stiles, 1893. 



Porocephalus is distinguished from T inguatula by its cylindrical 

 body and by certain internal structures. Porocephalus constrictus 

 is at present only known in its larval stage. It is milk white in 

 colour with golden-yellow booklets. Number of rings, twenty-three. 

 Length 13 mm., breadth 2' 2 mm. There are no prickles on the 

 posterior border of the annulations of the body. 



This species was first discovered by Primer encysted in the livers of two 

 negroes in Cairo. Bilharz reported two further cases in which the parasites 

 were encysted in the liver and in the mucosa of the intestine ; a few other observa- 

 tions have been made by Fenger, Aitken, Giard and Chalmas. Aitken's report deals 

 with soldiers of the British Colonies in Africa. The parasites were discovered in 



