326 DE W. CARMICHAEL M'INTOSH ON THE STRUCTURE OF THE 



these appearances may have been due to the action of the chemicals in mount- 

 ing, but they were very distinct. The ejaculatory duct has a single ring or coat 

 surrounding it. The exact arrangement of the fibres of this region is difficult to 

 unravel, but some evidently curve across the region, while those at the sides 

 bend backwards, the latter in some views simulating the walls of a cavity. In 

 Telrastemma vermiculus (as a living transparent object) the region has its deep 

 mass formed of fibres which curve outwards and forwards from the central set- 

 ting (Plate IX. fig. 12). Through this region the ejaculatory duct (fj) passes to 

 the point where it opens into the muscular space behind the constrictor of the 

 central aperture in the floor of the anterior chamber. The aperture of the duct 

 ii) is generally obscured by the central stylet- apparatus, unless the observer sees 

 it at the moment of contraction of the powerful muscular walls of the reservoir, 

 when the mucous or villous lining is driven forward so as to render the channel 

 more apparent, and a vigorous jet of the minutely granular fluid is propelled 

 into the muscular sac, and then through the stylet-aperture into the floor of the 

 anterior chamber. Closer observation, even when such convulsive contractions 

 are absent, occasionally shows the minutely granular fluid passing onwards to 

 the anterior chamber ; and when the ejaculatory duct is not obscured by the 

 glands, the dancing granules of this peculiar fluid are seen therein. Moreover, 

 when the large compound cells (Plate V. fig. 3) have been detached under pres- 

 sure, and squeezed forwards into the reservoir and along the duct, the calibre of 

 the opening into the muscular sac may be ascertained with tolerable accuracy, 

 and, so far as I could see, is such that only a single file of cells at a time can 

 be transmitted. The duct has a bent-conical form, a shape that avoids inter- 

 ference with the basal sac of the stylet, which occupies the centre of the region ; 

 and its posterior end (that opening into the reservoir) is capable of a certain 

 amount of constriction, as indicated in one of M. Claparede's figures, but I have 

 rarely met with the organ in this position. In the latter state the inner or 

 convex side of the duct is glandular, while the outer or concave side is not. 

 A layer of longitudinal fibres, continued from the reservoir posteriorly, consti- 

 tutes the proper wall of the tube, and is represented in transverse section 

 in Plate V. fig. 3. Internally the tube has a mucous lining, which anteriorly 

 is for the most part quite free from glandular papillae; a few small glands, 

 however, are generally observed towards its posterior end. Its wall is not very 

 dilatable, the cavity becoming elongated, but not much increased in diameter, 

 even under violent expansive force. It can be firmly closed by the contrac- 

 tion of the region surrounding it, so as to be marked by a mere central streak 

 (Plate XII. fig. 9, fx). The villous lining of the reservoir is often pushed forwards 

 along the duct during violent contractions. The whole structure of the channel, 

 and its relations to surrounding parts, show that it is formed, not for transmitting 

 fluids from before backwards, but entirely in the opposite direction. The mobile 



