EXPLANATION OF PLATES I & Il—continued. 
Fic. 8 x 225 diameters. Section of a seminal gland, testicular body. 
a, seminal duct with a branch passing off to a contiguous gland; 4, 
capsule of the gland formed by the expanded duct ; ¢, gland substance 
divided into irregularly shaped masses. 
Fic. 9 x 500 diameters. Components of the gland substance. 
a, spermatozoa amassed together; 6, free, aud showing the filamentary 
appendage. 
Fie. 10 x 140 diameters. Vertical section of the generative passages 
just at the genital pit, to show the relation of one to the other. 
a, penis; 4, vagina with the central canal oval. 
Fig. 11 x 140 diameters. Longitudinal section of the vaginal bulb near 
the external orifice. 
a, muscular portion merging into the thin walls of the canal generally. 
The dilatation is seen to be partially studded with pigmental granules. 
Fig. 12 x 140 diameters. Vagina near its termination in uterus. 
a, aspect of the canal generally ; 4, bulbous expansion near uterus; ¢, 
merging of the vaginal wall into that of the uterus. 
Fic. 13 x 225 diameters. Longitudinal section of a part of an immature 
segment, adjacent to the transverse canal, and embracing an ovarian 
gland which is small and has undergone no compression, either from 
within or without. 
a, transverse water-vascular canal; 3, visceral substance of a granular 
albuminoid nature; c, excavation in it, in which the ovarian gland lies ; 
d, ovarian duct; e, gland substance made up of amassed nucleated 
protoplasmic particles ; /; fibrous tissue wall of gland. 
Fic. 14 x 20 diameters. Anterior extremity of the tapeworm colony, the 
head and four suckers; to bring all the suckers into view, the head (a) 
has been bent upon the neck (4); ¢, cuticular lining of the sucker 
deeply pigmented ; d, fibrous envelope enclosing the special muscles ; 
e, depression in the centre of the head, corresponding superficially to 
the position of nerve-ganglion (?); from / to gis the course of the 
main water-vascular canal of the head, and also the line of junction of 
the fibrous layer between the dorsal and ventral pairs of suckers. 
Fie. 15 x 30 diameters. Vertical section through a sucker. 
a, cuticular surface of the body generally; 4, internal body-structure ; 
c, circular orifice of the sucker; ¢, cuticular lining from the external 
cuticle; e, deep layer of corium strongly pigmented; / fibrous en- 
velope; g, special muscles, radiating and circular; 4, longitudinal 
muscles of the colony inserted into the convexity of the fibrous 
envelope. 
Fic. 16 x 20 diameters. Transverse section through the neck of the 
colony. 
a, body-structure with inorganic nodules and muscular layers similar to 
the adult zooid; 4, visceral space containing granular albuminoid ma- 
terial in which the viscera are developed; c, longitudinal water- 
vascular canals. 
Fic. 17 x 225 diameters. Ova in different stages of development. 
a, earliest—a soft protoplasmic mass with nucleus and nucleolus; 4, 
divided nucleus and fat-globules in the protoplasm; c, further ad- 
vanced; d, a spherical double-walled flexible body, with nucleus greatly: 
segmented; e¢, segmentation complete; / separation of the com- 
ponents into future egg and granular surroundings; g, egg with 
radiating lines on the shell and enclosed embryo, granular particles 
collected into a mass; 4, egg-shell lightly coloured, but completely 
formed, external protoplasmic mass is irregular and soft, disintegrating ; 
?, egg freed from surrounding mass and mature, shell dark brown, with 
radiating small depressions, inner membrane loosely retaining the soft 
embryo armed with the six spikelets in pairs. 
