PROSTATE GLANDS OF THE EARTHWORMS OF THE FAMILY MEGASCOLECID2E. 447 
body-wall by strands which are continuous with the gland substance ; one strand 
in particular, passing from the dorsal end of the gland, extends upwards and 
becomes continuous with the lining of the body-cavity ; this seems to suspend the 
gland. Another stout strand passes from the lower end also. 
(7) Conclusions from the Study of the Prostate of Pheretima 
The mass of the prostate gland, with its ductules and main duct, is of 
mesodermal origin. 
(a) In the young stages the gland is continuous with the peritoneum, of which 
it appears to be a proliferation. 
(b) The intraglandular ducts are similarly continuous with the mass of the 
gland, and appear to arise as a tubular arrangement of some of the nuclei of 
the mass. 
(c) A capsule is not to be made out in many places in the young nor even in 
the adult gland ; where present it is a differentiation of the superficial portion of 
the gland. 
(d) There is no evidence of invagination or ingrowth of the surface epithelium. 
(e) Supernumerary prostates may occur, which consist of gland cells and 
ductules of normal type, but which have no connection with the surface of the 
body. If these are to be derived from an epithelial ingrowth, it would be necessary 
to maintain the unlikely supposition that the main duct had totally disappeared. 
(f) Attention has been drawn to the similarity of the gland cells to the pharyn- 
geal chromophil cells, which have been shown to be of peritoneal origin. 
The Prostate of Etjtyphcetjs. 
(l) The Adult Gland as seen in Dissection. 
The prostate of Eutyjphceus waltoni occupies segments xvii— xix, and may cause 
septum 19/20 to bulge backwards. It presents the form of a complicated coil, 
which is largely covered over on its inner face by a thin membrane (fig. 7). 
The glandular portion of the coil is opaquely white. Its commencement — in 
the’ example figured at about the middle of the outer (upper in the natural condition 
of the parts) border — is somewhat narrower than the main portion of the gland. 
The tube, winding much, first passes backwards ; then, curving round, its coils 
constitute the mesial portion of the hinder half ; then, passing forwards, the tube 
reaches the front end of the mass, and turns back again. Here it narrows very 
considerably, and soon losing its opaque character, becomes shiny, an indication 
of the loss of gland cells and development of the thick coat of circular muscular 
fibres. The duct winds somewhat, but is comparatively short, and pierces the 
body-wall in line with the inner or lower edge of the gland, in segment xvii. 
The bundle of penial setae in their sacs, bound together by connective tissue, 
