DR. NELSON ON THE REPRODUCTION OF THE ASCARIS MYSTAX. 
587 
Explanation of the Plates. 
PLATE XXV^. 
Fig. 1. Head of Ascaris mystax. a. The lateral ala or moustache, finely striated. 
h. The mouth with its three lips. c. The intestine commencing narrow at 
the mouth, and passing in a straight line along the axis of the body. 
d. The striated or horny bands of cuticle covering the body. Magnified 
30 diameters. 
Fig. 2. Tail of male. a. The dorsal aspect, h. The ventral, c. The anus. d. The 
genital orifice, f. Membranous projections, serrated on the edge and sup- 
ported by tubercles, g. Spiculse protruded to the natural extent. Mag- 
nified 30 diameters. 
Fig. 3. Male Ascaris mystax, natural size. a. The tail coiled up on the ventral 
aspect. 
Fig. 4. Female, natural size. a. The tail, not coiled, and coming to a blunt point. 
Fig. 5. Reproductive apparatus of the male. a. The convex dorsum of the tail. 
b. The concave ventral surface, c. The anus. d. The genital orifice. 
f. The part of the spiculum which is never protruded naturally, and is 
covered with tubercles for the attachment of the protractor and retractor 
muscles, g. The horny opake portion of the spiculum, which is protruded 
in coitus, h. The sheath of the spiculse into which they are withdrawn 
when not employed, i. The inferior portion of the intestinal canal, h. The 
seminal vesicle, covered by a reticulation of muscular fibres, m. The vas 
deferens, n. The testicular tube, filled with semen, a. The ceecal extre- 
mity of the testicle. Magnified 20 diameters. 
Fig. 6. Part of the spiculum. a. The protrusive portion, opake and tubular, c. The 
cartilaginous or non-protrusive portion, semi-transparent and of larger 
calibre than the horny, d. The tubercles to which muscles are attached. 
The joint between the two portions of the spiculum. 
Fig. 7* Part of the spiculum. a. The horny portion, h. The opening through which 
the semen esc3pes. 
Fig. 8. The ceecal extremity of the testicle, a. The thick granular membrane of the 
extremity from which the seminal particles are thrown off. h. The trans- 
parent and thin membrane of the testicular tube. c. The inner surface of 
the thickened extremity, showing its granular and irregular aspect, d. The 
seminal particles as they are first thrown off. Magnified 330 diameters. 
Fig. 9. Upper portion of the testicle, h. The membranous wall beginning to be 
slightly granular, a. The granules thrown off by the walls of the testicle. 
4 G 
MDCCCLII. 
