92 ILLINOIS BIOLOGICAL MONOGRAPHS [380 



crowded organs the appearance at first sight of being continuous thruout the 

 stroblla. 



The vagina was described by Liihe ( 1900a :68) as being provided with no 

 cuticular Unmg within the enlargement just beyond the sphincter, but in the 

 sections made by the writer the cuticula could be followed for about half the 

 length of the whole duct. Peripherally as in the case of that lining the terminal 

 enlargements, it was seen to be thrown into prominent longitudinal folds which 

 hi transections were in many places fused together so as to divide the lumen 

 into several passages. Farther on these folds become less pronounced and 

 fused, while their borders towards the center of the lumen gradually become 

 broken up into pseudociUa. Beyond the middle of the course of the duct 

 these pseudocilia seem to pass insensibly into the ciUa of the proximal region, 

 while the cuticula is likemse strictly continuous with the nucleated epitheHum, 

 there being no distinct region, let alone line of demarcation in either case. It 

 would appear, then, that what are apparently true ciha in the proximal portion 

 of the duct are merely modified cuticular pseudociha; or from the standpoint 

 of development that the latter, as well as the more peripheral ridges, are 

 formed by the gradual fusion of the former from within outwards. But since 

 this view needs considerable ontogenetic evidence for its support, it must re- 

 main for the present, at least, a mere suggestion of possibility. 



Otherwise the material studied, which was quite fragmentary, corresponded 

 with the descriptions given by the various authors of the species found on the 

 European side of the Atlantic Ocean, as was brought out by Linton (1890) 

 for the general features. It consisted of No. 13.46 of the Collection of the 

 University of Illinois from the stomach wall of Xiphias gladius, and one speci- 

 men taken by Mr. V. N. Edwards from a "Sunfish" (? Mola mola) at the 

 Woods Hole Laboratory of the U. S. Bureau of Fisheries. 



