Miscellaneous. 529 



Pteropods with 'J'loo Sfjxirttte Sexual Ojienings. 

 liy II. McE. K-vowEK. 



ITiiviiij; recently had occasion to review the anatomy of Cuvolinia 

 luni/iri)stris, by means of sections of spocimens obtained by the 

 U.S. Fish Commission schooner 'Grampus,' 1 Hnd that the stato- 

 ment in text-books and elsewliere, that uU Pteropods have but a 

 sinjjle external openiniij for the hermaphroditic sexual organs, is not 

 correct. Cuvolinia loivjirostris (to which species my specimens 

 apparently belong) has two distinct and separate sexual openings. 



There is a largo herma[)hroditic gland, lying ])osteriorly an<l 

 dorsally in the visceral sac, which is asymmetrical, being more 

 develoj)ed on the left side. In this gland tlie youngest ova aro 

 found in the centre, immediately around the iutraglandular jxjrtiou 

 of the duct, the oldest ova with considerable yolk at the periplierv. 

 The male elements arise from lines of cells running from the peri- 

 phery towards the centre. A single duct leaves the gland from its 

 anterior face, dorsally and far to the left, lleceiving the seminal 

 vesicle near this point of origin, the duct runs over to the right 

 towards the median plane. Near the middle line it opens into the 

 anterior face of a large glandular sac, which has much folded walls. 

 This sac is the muciparous gland, and the duct ends on reaching it. 

 Sections do not show a separate albumen-gland described for the 

 genus. They do show that some of the folds of the walls of the single 

 cavity of the gland are lined with non-glandular ciliated cells, while 

 others have distinctly glandular cells. The seminal vesicle is, as de- 

 scribed, a long saccular appendage of the duct, with its end dilated 

 and coiled up on the left side of the stomach. The muciparous or, 

 rather, uterine gland is quite largo ; it lies in the anterior portion 

 of, and occupies most of the left side of, the visceral sac. Quite 

 near the point where the hermaphroditic duct opens into the uterine 

 gland the vas deferens arises from the gland on its anterior riglit 

 corner, to the left of the median lino. This is a closed ciliated tube, 

 not a ciliated groove (in which this species differs from all other 

 Pteropods), which curves around on the right to the dorsal surface 

 of the fins, to run anteriorly and open at the sac of the invaginatcd 

 penis. On the left side of the uterine gland sections in all planes 

 show a second opening from the reproductive si/atem to the exterior. 

 This is a slit-like aperture on a slight papilla, on the anterior surface 

 of the visceral sac and to the left. The opening leads dii-ectly into 

 a ciliated fold of the uterine gland, the ciliated cells of which turn 

 out at the lips of tho aperture and become continuous with the 

 epithelium of the external surface of the body. There can be no 

 doubt that this is a natural opening, and near it is found the seminal 

 receptacle, a thin-walled sac filled with spermatozoa and lying on 

 the left face of the uterine gland. This seminal receptacle opens 

 into a fold of the uterine gland, not far from the external opening 

 just described, which I take to be a vaginal opening. 



