276 Henry Leslie Osborn, 



They are of about equal size, measuring 0,25 mm in diameter. The 

 ventral sucker is located only slightly posterior to the level of the 

 centre of the body (see Fig. 4), which is much further forward than 

 the position assigned to it in Nickerson's drawing. Both of the 

 suckers were inactive in the living worms, while they were under 

 observation. 



The position of the genital opening is shown in Figs. 3 and 4. 

 It lies dorsally and on the left of the middle line. As pointed out 

 in my former paper both Stafford (1900) and Nickerson (1900) 

 were in error in stating that it is ventral. In respect to this 

 dorsal position of the pore, Loxogenes is quite unique. In most 

 trematodes the opening is located in the mid-ventral line between 

 the oral and ventral suckers, it may however have a number of 

 other positions. In Pleurogenes it is lateral, the position in Loxogenes 

 is a still greater deviation than that of Fleurogenes. 



In Nickerson's drawing of Loxogenes (1900, fig. 1) the termi- 

 nations of the ejaculatory duct and of the uterus are represented 

 as if one were somewhat distant from the other and as if there 

 were two openings. This is not in accordance with the structure 

 of my material. In surface views of the entire worm one can see 

 that at the surface the genital opening is single, but just within 

 the contour of the opening there is a light colored bar of tissue. 

 This marks the boundary between the two genital ducts, which meet 

 at the surface at a common opening. There is thus no genital 

 atrium. The exact relations of the terminations of these ducts and 

 their relation to the surface is best determined by means of a sec- 

 tion passing vertically to the surface in the plane of the genital 

 pore. Such a view is shown in Fig. 5 taken form a transverse 

 series. At g^m the cuticula of the outer surface bends inward and 

 becomes continuous with that which lines the genital passages. 



b) Internal Features. 

 The Alimentary System. 



The oral sucker lies in the extreme anterior end of the body. 

 It is globular in form and has a diameter of about 0,2 mm. Its 

 wall exhibits the usual muscular structure thickened by the presence 

 of a mass of radial fibres usual to adhesion organs. The cuticle is 

 present, it does not possess spines. The oral sucker is followed by 

 a smaller pharynx whose wall shows the usual histological structure. 



