WAGENER_, ON GYRODACTYLUS ELEGANS. 205 



The sexual system consists of the single testis, and a horse- 

 shoe shaped ovary. 



The testis is a usually spherical or sometimes heart-shaped 

 sac, the base of which is directed upwards. It is situated 

 beneath the back of the animal, between the two branches 

 of the ovary and of the intestine, its base reaching the horse- 

 shoe shaped commissure of the former. Its upper wall 

 slightly overlaps the oviduct, where the ovum is delayed 

 before its entrance into the uterus. The wall of the testis 

 exhibits a double contour line ; the vas deferens is a short 

 tube, which appears to penetrate the upper wall of the 

 oviduct. 



The common sexual orifice — that is to say, of the oviduct and 

 testis — constitutes a papillteform elevation, projecting from 

 the inferior wall of the uterus into its cavity. 



The contents of the testis are sometimes composed entirely 

 of cells ; sometimes half of the sac is filled with a clear fluid 

 containing either active spermatic filaments in tumultuous 

 motion, or the well-known mulberry-shaded globules beset 

 with spermatic filaments, associated also with immobile 

 filamentary bodies. Occasionally, also, an apparently virgin 

 ovum may be seen in the oviduct surrounded with spermatic 

 filaments, some of which may likewise be now and then 

 perceived in the uterus itself, before its cavity is entirely 

 occupied by the ovum. 



The spermatozoa themselves are simple filaments, having 

 no distinguishable cephalic extremity, except that one end 

 seems to be a little thicker than the other. 



The ovary is of large size, and occupies almost the entire 

 lower half of the animal ; it is very transparent, and usually 

 of a horse-shoe form. Its upper extremities reach above the 

 lower wall of the uterus, to an extent corresponding with the 

 degree of distension of that organ. 



The length and breadth of these glandular lobes depend 

 upon the state of development of the ovary ; and the upper- 

 most of them, occasionally slightly hollowed, expands so as 

 to embrace the intestine which rests upon it. 



The gland is situated beneath the neutral surface. It is 

 subdivided by shallow grooves into segments, which vary in 

 different individuals, and are probably due to the formation of 

 the ova. Each segment consists of a very clear matrix, in 

 which transparent nuclei with nucleoli of pretty uniform size, 

 though at irregular distances apart, may be noticed. Near 

 the oviduct, a portion of the matrix appears separated from 

 the surrounding substance by a circular line, encompassing 

 and concentric with a nucleus. The oviduct appears to 



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