280 Henry Leslie Osborn, 



sheath, the cirrus sack, enclosing the glandular cells (prostate gland), 

 just mentioned. 



We now turn our attention to the cuticula of the vagina. The 

 fact that this cuticula is covered with papillae has been known 

 since the time of Noack who refers to them in his account (1892) 

 of Distomum (now Pleurogenes) clavigerum. Looss (1894) shows them 

 in his figures of the same form. The wall of the vagina in the 

 region of the letter v of Fig. 5 was very carefully examined under 

 an oil immersion objective, in sections after fixation in Gilson's 

 fluid and iron-haematoxylin staining. Fig. 6 is made from a camera 

 lucida drawing from this wall. The glandular portion of the wall 

 is merely indicated in outline on the left, the cell boundaries are 

 not worked out and the nuclei are merely sketched in. 



The cuticula is seen on the right. It presents two zones, the 

 papillae and the deeper zone. The latter is a structureless and 

 homogeneous material which has very little affinity for stains. It 

 is a continuous structure without internal boundaries of any kind. 

 It measures 0,02 mm in thickness. The papillae are direct out- 

 growths of this material and in height about equal its thickness. 

 Each one arises from a broad outgrowth of the deeper zone and 

 tapers gently to an obtuse apex. The papillae in the vagina are 

 larger, more distinct and fewer than those in the male duct. 



We pass now to notice the spines in the cuticula of the vagina. 

 Four of these are shown in Fig. 6. A view from the spines, cut 

 transversely, is given in Fig. 7. The section passed in the level of 

 the deeper zone and shows the spines imbedded in a continuous 

 unstained medium, the cuticula substance. Although these structures 

 are located in such an unusual position, there can be no doubt as 

 to their complete identity with the spines of the outer surface. 

 Their relation to the cuticula is the same and their action toward 

 the various reagents is the same. These vaginal spines measure 

 0,01 mm across the base and 0,03 mm in length. They become very 

 slender and acute as they extend toward the tip. They lie almost 

 entirely in the deeper zone of the cuticula, in some cases the tip 

 of a spine extends out into the bases of the papilla a short distance. 



A characteristic portion of the wall of the ejaculatory duct, 

 from the region indicated by dj in Fig. 5, is shown in Fig. 8, which 

 has the same magnification as Fig. 6, of the vagina. The whole 

 thickness of the cuticula is less, being 0,025 as compared with the 

 0,05 mm of the vagina. The papillae are present, but they are 



