PROSTATE GLANDS OF THE EARTHWORMS OF THE FAMILY MEGASCOLEC1DFE. 453 
Fig. 2. Portion of a lobule of prostate -of P, hawayana in section. This part of the section is near 
the margin of the gland, where it is only one lobule thick. There is no distinct capsule anywhere ; where 
the surface of the lobule is shown as a definite line, as at x, it indicates only that the superficial margin of 
the “ cells ” is clearly defined, and appears as a definite line. x 400. 
d., ductule; fib., fibrillar differentiations in gland substance; gran., aggregates of granules; vac., 
vacuole-like spaces. 
Fig. 3. P. hawayana ; edge of two adjacent lobules in section, showing separate cells. A transition 
zone is to be seen at the right-hand side of the figure, where the cells are passing into the ordinary structure 
of the gland substance. There is a distinct capsule separate from the cells, x 700. 
caps., capsule; gran., granules; x, cells showing darkly staining masses in their interior; these are 
very similar to the chromophil cells of the pharyngeal glands. 
Fig. 4. Supernumerary prostate of P. haivayana ; central part of a lobule in section. The uneven 
character of the constituent portions is obvious, x 370. 
b. v., capillaries; d., ductule ; fib., fibrillar differentiations, often appearing to mark out cell territories. 
. Fig. 5. Tip of developing prostate of P. hawayana (probably). Two sides of the cell-mass are on 
the surface of the gland; there is, however, no peritoneal covering. _x 730. 
a, aggregate of cells arranged round a lumen ; b, more or less spherical aggregates in which no lumen 
is present; c, irregular aggregates ; d, nuclei in the spaces between the cell aggregates. 
Fig. 6. An early stage in the development of the prostate of P. hawayana (probably). x 350. 
c. t., 'connective tissue — the thickened peritoneum; long., longitudinal muscle layer of the body-wall; 
.in., muscular fibres cooling into relation with the developing gland; pr., developing prostate. 
Fig. 7. Prostate of Eutyphoeus waltoni, left side, as seen in dissection ; successive portions of the 
coil are numbered consecutively, x 8. 
a, beginning of coil ; c.t., band of connective tissue, in which are contained penial setae in their 
sheaths; int., intestine ; pr. d., prostatic duct; v. def., vas deferens. 
Fig. 7a. Terminal portions of prostatic duct and vas deferens of the above, with the end of the 
bundle of penial setae, x 15. 
Fig. 8. Section through portion of wall of prostate gland of E. waltoni. The section passes longitudi- 
nally along a part of the glandular tube, and one-half of the thickness is shown, i.e. the whole depth of 
the wall on one side of the lumen ; the lumen is upwards in the figure. The deeply staining (blue with 
hsematoxylin) granules are represented darker than the more lightly staining (with eosin) granules, x 400. 
a, deeply staining gland cells of inner layer; b, cells of outer layer ; b.v., capillaries; caps., delicate 
capsule on outer surface of gland ; to., muscle fibres. 
Fig. 9. Dichogaster malayana ; part of a longitudinal section of the anterior end of the worm, passing 
through a portion of a prostate gland. There is no hint of a capsule, except at x, y, and possibly z. The 
attachment of the gland to the septum is such, that, where this occurs, at a, the gland cells actually constitute 
the septum: there are no other constituents, x 160. 
d. w., the peritoneum of the dorsal body-wall ; sept., the septum, from which the gland has apparently 
proliferated. 
Fig. 10. Ocnerodrilus occidentalis ; an early stage in the development of the prostate, x 500. 
c.to., circular muscular layer of the body-wall; c.t., connective tissue cells; ep., surface epithelium; 
l.m. , longitudinal muscular layer of body-wall ; pr., the young prostate. 
