DUBLIN NATURAL HISTORY SOCIETY. 55 



believing that the uterus secretes those beautiful rhombic crystals 

 of carbonate of lime seen on the egg of this animal, inasmuch as I 

 have not found them upon those ova which had just entered the upper 

 sacculi, whilst those situate in the lower ones were invariably studded 

 with them. 



The male organs lie to the left of the female, and include the testis, 

 vas deferens, and penis, with its flagellum. The first, as before men- 

 tioned, is closely united to the uterus, commencing and terminating 

 with it ; nevertheless, it is a very distinct and extensive structure, and 

 deserves far more attention than has been heretofore bestowed upon it. 

 It consists of a central duct, closed at its posterior extremity (as shown 

 by the obstruction to liquids introduced as injections), Avhich is beset 

 on its sides by two rows of long white granular-looking follicles. These 

 are observed, under the microscope, to open into the central channel, 

 and to contain those oval and elliptical epithelial-like cells, usually de- 

 scribed as the parents of zoosperms. The central vessel now leaves the 

 testis, at the point of union of the uterus and vagina, and is continued 

 as a simple duct for a distance of an inch and a half, or thereabouts, 

 when it terminates by a rounded aperture in the penis. It is this por- 

 tion to which the term vas deferens has been applied. The penis is 

 represented by a long attenuated tube, wide, and of rather thickish con- 

 sistence at its base, which is perforated, and communicates with the 

 generative outlet, coecal at its apex, which is extremely delicate, and 

 situate deeply in the mass of viscera. It communicates with the vas 

 deferens by a small aperture, distant from the basal opening about an 

 inch and three-eighths, and measures, fr-om end to end, when extended, 

 about three inches and a quarter. The blind extremity, from its fan- 

 cied resemblance to a whip-lash, has been termed the flagelliform por- 

 tion. About the junction with the vas deferens, there exists, attached 

 to the penis, a strong muscular fasciculus, which probably performs the 

 function of drawing back this organ after it has been everted in copu- 

 lation. 



The androgynous group includes the vagina, vas deferens, and sperm- 

 sac, with its duct and coecum. 



The vagina is usually described as the termination of the uterine 

 portion ; but from the direct continuation which it forms with the copu- 

 lative vessels, and its almost rectangular connexion with the uterus, it 

 seems more correct to look upon it as the dilated extremity of the former. 

 Viewing it thus, both may be said to constitute a tube, leading from 

 the dart-sac, on the one hand, to the sperm-sac, on the other, wider at 

 its proximal than at its distal end, about one inch and three-eighths in 

 length, and one-sixteenth of an inch in diameter, following a back- 

 ward course, beneath the superficial viscera, toward the anterior margin 

 of the liver, where it expands abruptly into a spherical or pyriform 

 bag — the spermatheca, or sperm-sac. This vesicle, whose office appears 

 to be the storing up of the semen received during coition, varies in its di- 

 mensions under different conditions. Thus, immediately after union of 

 the sexes, when distended by its seminal contents, I have often found 



