Loxogeues arcaniim Nickerson. 279 



outer end of the uterus is spinous as well as the ejaculatory duct, 

 and this will be discussed later. 



The V i t e 11 a r i a are confined wholly to the anterior end of the 

 body. Their follicles lie in a layer near the ventral surface. They 

 are uniformly arranged and not grouped so as to form distinct right 

 and left organs as in B. medians. Posteriorly they do not extend 

 quite to the level of the anterior borders of the testes. The follicles 

 themselves are numerous and small, measuring about 0,09 mm by 

 0,06 mm. Their ducts were not recognized either in the whole 

 animal or in sections. The very small and inconspicuous yolk-duct 

 enters the oviduct at the shell gland. 



The coils of the uterus are distended with the eggs which are 

 immensely numerous. In addition to these many eggs had passed 

 from the animal and were at large in the cavity of the cyst. The 

 eggs measure 0,024 mm by 0,014 mm.^) 



IV. On the spiues of the outer ends of the genital passages, and 

 of the cavity of the ventral sucker. 



It was noted in my previous paper (1912) as a fact of unusual 

 interest, because it is unique among trematodes, that the cuticula 

 of the outer ends of the genital passages is clothed with spines."^) 

 This point is of sufficient interest to receive further notice and a 

 detailed account of this cuticle now follows. 



As shown in Fig. 5 the cuticula on being infolded at once be- 

 comes very much thicker. It is thinner at the genital pore than 

 elsewhere on the surface measuring 0,005 mm, but in the genital 

 ducts it increases to a thickness of 0,03 mm. Spines make their 

 appearance almost at once and continue in the cuticula throughout 

 most of the length of the ejaculatory duct and the vagina. The 

 structure of the wall of these organs is similar but there are cer- 

 tain difterences in details. The wall is composed of two coats in 

 both : an outer cuticula with the papillae and spines, next the lumen 

 of the organ. Enclosing this coat there is a second deeper coat 

 composed of glandular cells, placed radially around the surface coat. 

 In addition to these there is in the male duct a distinct muscular 



1) The measurements in my paper of 1912 p. 556 should apply to 

 the yolk follicles and not to the ova. 



2) It has recently been noted by "Watson, 1911, that spines occur 

 in a similar location in the cestode Gyrocotyk. 



