266 Proceedings of Indiana Academy of Science 
. Sub-family; Metastrongylidae. 
. Genus; Metastrongylus. 
. Species; M. apri. 
. M. brevivaginatus. 
Aan 
DESCRIPTION. 
M. apri: Cylindrical, unsegmented worms; body long and slender; 
buccal capsule absent or slightly developed; mouth with six lips; dorsal 
and externodorsal rays slender, the other thick; postero-lateral ray 
reduced or absent; females often show a dark hair line throughout their 
length; cuticle transversely striate. Male: 12 to 17 mm., average 
length, 16 mm.; spicules very long (about 4 mm.), and each terminates 
in a single barb; bursa deeply bilobate, opens laterally; five costae in 
each lobe; spicules segmented, cylindrical, capable of being coiled up 
within the bursa or of being withdrawn into the body cavity; dark 
brown, reticular tubes of chitin; fleshy portion consists of a membrane 
which is attached by a bulb like expansion to the seminal vesicle. Fe- 
male: 2 to 4 em.; vagina about 2 mm. in length; vulva close to anus, 
and on a slight eminence in front of it. Eggs contain living embryos 
coiled within them, and range in length from .05 mm. to .08 mm. The 
width averages .02 mm. less than the length; tail of female terminates 
in a short horn-like process; embryos when liberated measure .22 to 
.25 mm. in length, and .01 to .012 mm. in thickness. 
M. brevivaginatus: The same general description applies to this 
species as to M. apri. Male: 15 to 20 mm. long; spicules 1 to 1.5 mm. 
long; body and bursa larger, stouter and more conspicuous, than in 
preceding. Females: 3 to 5 em. long; eggs .07 to .10 mm. long and 
.05 to .08 mm. wide; larvae somewhat larger than those of M. apri. 
MORPHOLOGY. 
When viewed under a low power objective, the structure of these 
parasites is found to be relatively simple. In both sexes there is a dark, 
well defined, digestive tract traversing the entire length of the in- 
dividual. This tract communicates with the mouth by means of a mus- 
cular, conoid esophagus, and terminates in a ventral anus near the 
posterior end of the body. Worms that are full grown show the body 
cavity to be almost completely filled with enlarged and convoluted re- 
productive organs. These, together with the alimentary tract, so com- 
pletely fill the body cavity that there remain only here and there small 
irregular spaces. In the female the oviduct becomes continuous with 
the uterus, a short distance behind the esophagus. It then pursues a 
course parallel to the intestine, until it terminates in the vulva on a 
slight prominence in front of the anus. The reproductive organs of 
the male consist likewise of a single tube. However, this tube is not 
bent upon itself, as is the case in the female, but is single and tapering, 
and constricts to form the testicles and the seminal vesicle. To the 
terminus of this last are attached the two spicules, which function in 
copulation. The body of the female terminates in a blunt horn-like 
projection, that of the male in a rather complicated, membranous, clasp- 
ing apparatus. During copulation the male grasps the female with this 
structure, and impregnates her by inserting the spicules already men- 
