484 H. F. MOORE. [Vol. X. 



are arranged at different depths, and the duct-like prolonga- 

 tions are consequently of various lengths. I was unable, ex- 

 cept in one or two doubtful cases, to follow the individual cells 

 to their openings into the atrial cavity, but many could be 

 traced for about half of the distance, when they became lost in 

 the multitude ; others could be followed from their orifices out- 

 wards to about the same region, and as there was no difference 

 in appearance it is but reasonable to assume that these glan- 

 dular cells open by their long necks into the cavity of the 

 prostate. I have in many cases all but absolutely demonstrated 

 the continuity. 



Chitinous spicules, or fibres, project from the mouths of 

 these cells into the cavity of the prostate, or as is more accu- 

 rate, into the atrial cavity, Benham having shown that this 

 cavity is atrial whilst the term prostate should, in strictness, 

 be applied to the glandular cells only. The chitinous filaments 

 may, in many cases, be followed some distance into the necks 

 of the cells, which latter I shall designate as chitinogenous 

 glands. They are the most abundant cells of the prostate, and 

 in the region in which they open the columnar atrial cells are 

 comparatively few in number. Fig. 1 8 shows a portion of this 

 region with the chitin spicules projecting from the mouths of 

 the cells. Fig. 1 5 shows a section through the prostate from 

 central cavity to circumference. 



The second form of gland cells, although constituting a 

 large portion of the walls of the organ which I have here called 

 prostate, are perhaps not to be accounted homologous with the 

 prostates of other worms. 



These cells are also club-shaped, and their swollen inner 

 ends are somewhat larger than the corresponding portion of 

 the chitinogenous cells, and also appear to be rather more dis- 

 torted through mutual pressure. They are arranged in bunches, 

 or lobes, between which the coelomic membrane passes for a 

 short distance. The ducts, or necks, of these cells (Fig. 16) 

 are longer than those of the chitinogenous cells, and are 

 arranged in a manner more strictly parallel to one another. 

 The entire cell is filled with a granular material which stains 

 deeply, and the nucleus is noticed as a more homogeneous 



