NEMATOIDEA. 355 
Naturalists have lately separated from the Ascarides and- 
Strongyli the 
SPIROPOPTERA, 
Where the body terminates spirally, and is surrounded by two wings 
from between which issues the penis(1). 
One species is said to be occasionally found in the human 
bladder. Another, the 
Sp. strumosa, Nitsch, inhabits the Mole. It penetrates into 
a ring which it forms in the -villous coat of the stomach, and 
attaches itself there by a small tubercle(2). 
PHYSALOPTERA. 
Where the posterior extremity is provided with a bladder between 
two little wings, and a tubercle from which the penis originates(3). 
ScLEROSToMA, Blainv. 
Where the mouth is furnished with six small dentated scales. 
They are found in the Horse and in the Hog. 
Lioruynouus, Rud. 
Where the mouth is in the form of a little proboscis(4). 
Pentrastoma, Rud. 
Where the body is depressed and trenchant on the sides, and the” 
transversal ruge are marked by numerous crenulations. The skin 
is thin and slight; the head broad and flattened; and the mouth be- 
neath; on each side of the latter are two small longitudinal clefts 
(1) Rud., Syn., p. 22. 
(2) Nitsch, Monog., Gm., Hal. Sax., 1829. 
(3) Rud., Syn., 29. 
(4) Rud., Hist., Il, 247, et seq. 
