

BY WILLIAM A. HASWELL, M.A., B.SC. 659 



The wall of the duct is lined by a granular ciliated epithelium. 

 The walls of the gland have an epithelium similar to that already 

 described in the case of Eupomatus, with highly granular cells and 

 long cilia ; but the cells are very much smaller, being only 

 about ^th of an inch in long diameter, and the cilia are not so 

 numerous and much more delicate. The epithelium of the outer 

 sac is much thicker and nfore densely granular than that of the 

 inner ; it is richly supplied with pseudohcemal vessels. At 

 intervals among the granular cells lining the sac occur others 

 which are transparent and free from granules. Here and there 

 among the granular cells are opaque mulberry-like or spherical 

 concretions, which are seen on a close examination to be made up 

 of agglomerations of granules. 



In Pomatoceros, (pi. XXXV., fig. 2, t.g., fig. 3, and fig. 4), 

 as in the other genera, the common excretory duct of the 

 glands opens upon the anterior and ventral aspect of the head 

 between the bases of the branchiae ; it runs backwards along 

 the ventral side of the depression separating the prrestomial lobe 

 from the lips of the alimentary canal, forming a conspicuous ridge. 

 In this situation its wall is formed (1st) of a continuation of 

 the cuticle of the surface of the head (2nd), a layer of hypoderm 

 which differs from that around in being composed of short 

 columnar cells (3rd), a layer of fine connective tissue with perhaps 

 muscular fibres, and (4th), the epithelium, which is composed of 

 cubical or polyhedral cells filled with brown granules. In the 

 connective tissue layer are a few pseudohaemal vessels. A little 

 further back the common duct bifurcates, the two branches each 

 forming almost a right angle with it, and each opening into the 

 gland of its side. Each gland consists of a single elongated sac 

 occupying a lateral position close to the body-wall. I can find no 

 opening into the perivisceral cavity. The walls of this sac are much 

 folded and are of considerable thickness and great opacity. They 

 are formed, besides an outer connective and muscular coating 

 with numerous pseudohaemal vessels, of a very thick and dense 

 layer of elongated cylindrical epithelial cells (fig. 4) densely packed 

 with yellowish-brown granules. These cells are much smaller 



