68 Prof. J. Van der Hoeven on the Anatomy 



margin convexly prominent, especially at the upper part. If 

 the thin but strong integument of this part be removed, then 

 the testis presents a brownish-yellow colour, and is seen to be 

 divided into an upper and a lower half, and by transverse furrows 

 that run obliquely into some loosely connected lobes. It is 

 composed of a quantity of acini, which, with their blind extre- 

 mities on the surface, look like white spots. The proper com- 

 position of the tissue of these acini was not apparent; the mi- 

 croscope indicated nothing but a granular mass. On the inside 

 of the testis white ducts are seen which meet in a tube {vas 

 efferens) that runs at the right side. This tube leaves the tissue 

 of the testis, runs for a short space within the tegumentary sac, 

 and terminates on a flat conical prominence by a small oblique 

 aperture. The margin of this papilla presents radiating folds, 

 and is in close union with the covering of the testis, which is 

 perforated by the aforesaid aperture. 



Above, and on the right side of the testis is situated a second 

 gland, of a flat form, longitudinally round and smaller than the 

 first*. It consists in part of many small lobules attached to 

 flattish transverse partitions, and formed of microscopic finger- 

 shaped blind tubules whose walls consist of cylindrical or conical 

 cells (cylinder -epithelium) . In the anterior extremity of this 

 second sexual gland a saccule placed transversely is included, and 

 is surrounded below by its tissue (PL VI. fig. 2). Behind this 

 saccule is seen a milk-white body, in which I afterwards recog- 

 nized, from the observation of Dr. J. A. Bogaard, Prosector of 

 the Leyden University, who investigated the sexual organs of 

 Nautilus with me, the convolution of a tube. I succeeded in 

 following the course of this tube further, which was somewhat 

 difficult, since it is in close connexion with the tissue of the 

 gland, and for the most part is concealed in the innermost por- 

 tion of it. At its anterior extremity this tube terminates between 

 the two slips of a nipple at the right side of the above-named 

 saccule, then follows a course to the left towards the posterior 

 margin of the saccule, then makes marked convolutions directed 

 downwards and upwards and lying close together, afterwards 

 proceeds, close along the right margin of the gland, backwards, 

 again penetrates more into its depth, and finally ends as a fine 

 canal of about | millim. in diameter. The aperture of this fine 

 canal, scarcely visible to the naked eye, is situated on the left 

 side of the gland, which there presents a longitudinal furrow 

 opposite to the conical excrescence in which the vas efferens of 



* It now appears that it was this second gland which, in the imperfect 

 specimen described by me in 1847, I saw in fi'ont of the testis (" a round 

 mass that fell from the visceral cavity." Tijdschr. uitgeg. door de eerste 

 klasse van het Kon. Nederl. Instituut, i. bl. 72). 



