152 ONYX AND DIPELTIS, 



the body. The rectum is of the usual form. There is no pre- 

 rectal portion as in Dorylaimus. 



The female sexual apparatus is double and symmetrical, each 

 ovary being reflexed. The vagina is well developed, and is 



to 



h 



supplied with a chitinous lining 

 and the usual vaginal glands. The 

 male sexual apparatus is double 

 and commonly directed forward 



Fig. 7.— Profile View of the Vulva of 



Onyx perfectis. the chitinous vagina throughout its extent, but SOme- 

 is shown dark, and two unicellular . . 



glands are shown light, x 225. times having the ends or the tes- 



ticles reflexed. The ductus ejaculatorius extends along that 

 portion of the belly occupied by the row of accessory organs, 

 and appears to be composed of a double row of cells much flattened 

 in the direction of the axis of the body. The free extremity of 

 each testicle is filled with from fifty to one hundred elongated 

 structures arranged radially, but directed obliquely towards the 

 axis of the organ. These bodies are granular and stain in carmine. 

 They increase rapidly in size posteriorly and become the mother- 

 cells of the spermatozoa, which they appear to do by a conden- 

 sation of the granular matter contained in them into a distinct 

 nucleus. The flattened mother-cells are packed in two or three 

 rows after the manner of a string of dried figs, but begin so soon 

 to break up that it is often impossible to count more than twenty 

 of them. The spermatozoa resulting from the breaking up of the 

 mother-cells are distinctly nucleated, spheroidal, granular bodies 

 whose diameter is one-fifth to one-fourth as great as that of the 

 testicle. There are two spicula, and they are supplied with 

 accessory pieces. On the ventral line a single row of preanal 

 accessory organs is found, coextensive with the ductus ejaculatorius. 

 Caudal glands are found in both sexes. The posterior part of 

 the tail, or terminus, is larger than usual, conical and destitute of 

 strise. 



In another journal* I have called attention to the existence of 

 striae in the cuticula of two species of Dorylaimus, and ventured 



* Jenaische Zeitschrift fur Naturwissenschaft. xxiii. Bd. 



