40 ENTOZOA FOUND IN MAN. 



the larva sometimes possesses vital properties distinct 

 from those of the adult, and it is able to resist the 

 action of agents which would rapidly cause the 

 destruction of the full-grown worm. 



Section A. — Nematoidea in the Larval State. 



Nematoideum Tracheale. 



This is a very minute larval nematoid worm, 

 which has been only once observed by Mr. Rainey, 

 who found several of the entozoa to which this name 

 has been given, in the larynx and trachea of the body 

 of a man. 



These worms, which existed in a free state, 

 exhibited great liveliness when they were first exa- 

 mined by the microscope ; their movements gradually 

 ceased, and some of the worms became rolled up in 

 such a manner as to resemble a trichina when it is 

 enclosed within its cyst ; the others remained almost 

 straight. 



A full description of the Nematoideum tracheale 

 is contained in the " Transactions of the Pathological 

 Society for 1855." 



Section B. — Nematoidea in the Perfect State. 



Genus Oxyuris. 



In the entozoa included in this genus the body is 

 cylindrical, or almost fusiform, tapering oif posteriorly 

 in the female ; the head is not armed with hooks ; 

 the mouth is round when it is contracted, triangular 

 and three-Hpped when it is projected. 



