42 A FAUNA WITHIN ANIMALS. 



§ 1. Description of a SrECiES of Ascaris. 

 1. Ascaris infecta, Leidy. 



Proc. Acad. Nat. Sci., Phila., iv., 229. 



(Plate VI. Figs. 1, 2, 6, 7; VII. Figs. 5, 11, 14, lG-20, 22.) 



Body nearly cylindrical, attenuated posteriorly, obtusely rounded anteriorly, 

 white, translucent, with the brownish intestine faintly visible through the in- 

 tegument; tail long, conoidal, curved, acute ; lobes of the mouth prominent. Buccal 

 organ (oesophagus) robust pyriform, or oblong and dilated below; gizzard short, 

 cordiforra; intestine cylindroid, narrowing posteriorly, slightly dilated at com- 

 mencement; rectum elongated, obpyriform, oblique. 



Male relatively more cylindrical, with the posterior extremity incurved (PI. VII. 

 5, o) ; furnished ventrally upon each side anterior to the anus, with a longitudinal 

 row of four minute conoidal tubercles connected by delicate folds of integument; 

 tail relatively thicker and shorter, furnished upon its ventral surface with two 

 minute conoidal tubercles. Penis compcsed of two equal acinaciform spiculse, 

 about I of a line long. 



Length 2 lines; breadth at origin of intestine jl--^ of an inch; at middle ^yo of 

 an inch; just anterior to anus -^^^ of an inch. Length of tail from anus y|^ of an 

 inch. 



Female, straight (PL VII. 5, h). Generative aperture just posterior to the middle, 

 prominent. Vagina furnished with a large oblong ovate spermatheca. 



Length of adult 3 to 4i lines; breadth anteriorly ^Jg of an inch; at middle -^-^ 

 to gJ^ of an inch; posteriorly y|„ of an inch. 



Ova oval, 3^3 inch long, by -^^-^ inch broad. 



Especial Hahitation. — Found constantly within the ventriculus of Julus marginatus, 

 occasionally within the large intestine. It is sometimes very numerous, of various 

 ages and sizes. The males are found in proportion to the females about as one to 

 eight. 



§ 2. Habits and Anatomy of Ascaris Infecta. 



This Ascaris is frequently observed clinging by means of the mouth to the epi- 

 thelial lining of the ventriculus of Julus (PI. VII. 5). 



In copulating, the male hangs in a sigmoid curve backwards from the female, the 

 spiculaj of the penis introduced within the vagina of the latter (11). 



Anatomy. — The buccal organ is very broad and strongly muscular. Its length is 

 about the ^V of an inch in the female and about two-fifths less in the male (PI. 

 VI. 1, a; 2, h). 



The gizzard is strongly muscular, and nearly as broad as it is long (1,&; 2,c). 



