436 " THETIS " SCIENTIFIC RESULTS. 



The left visceral connective [I. v. con.) rises from the right hand 

 side of the supra-intestinal ganglion. The rig?it visceral con- 

 nective (r. V. con.) rises from the left hand side of the sub-intes- 

 tinal ganglion. 



The right niaritle nerve (r. m. n.) rises from the right hand 

 side of the sub-intestinal ganglion. The left mantle nerve (l.m.n.) 

 takes origin from the left cerebral ganglion near its base. There 

 is a branchial nerve ihr. n.) given off by the supra-intestinal 

 ganglion. This branchial nerve and the left mantle nerve 

 anastomose, and give rise to a dialyneurous conditiori: on the left 

 side. 



The columellar nerve {col. n.) arises from the left cerebral gang- 

 lion, just above the mantle nerve. 



The cerehro-huccal con7iectives (c. biic. con.) originate from the 

 cerebral ganglion ; the left from near the base of the loop on that 

 side ; the right from near the top of the loop on the correspond- 

 ing side. 



Between the right visceral connective and mantle nerve there 

 arises a nerve {gen. n.) which I am inclined to regard as genital, 

 but am doubtful about it, not having been able to find its ultimate 

 branches. 



Three or four nerves arise from the right cerebral ganglion, 

 about which nothing is known. 



6. Reproductive Systems. 

 (PI. xl., fig. 5.) 



Male — The gonad, as is usual, is situated around the digestive 

 gland near the end of the visceral coil, it is of a yellow colour 

 and not very large. 



The vas-deferens passes forward along the right side of the 

 digestive gland, on the surface of which, just behind the nephri- 

 dium, it is much coiled ; it then turns down to the axis and 

 passes forward below the nephridium. In the mantle cavity it 

 lies on the mantle close to the body on the right side, about 

 half way forward along the cavity it makes an S-shaped curve and 

 comes to lie on the body {v.d.), where it is plainly seen as a ridge 

 passing forward to the base of the penis. 



The penis {p.) is remarkably large ; it is carried folded back upon 

 itself, and lying in the mantle cavity along the right side of the 

 body parallel with and just to the left of that portion of the vas- 

 deferens attached to the bod}'. In the figure the penis is repre- 

 sented raised up and bent slightly to the left, so that the vas- 

 deferens may be shown. The former is attached to the body well 

 forward, just a little behind and to the right of the tentacle lobe; 

 in transverse section it is oval, its shape otherwise is shown in 

 the figure. The ductus ejaculatorius passes through the penis 



