782 



ZOOLOGY 



aperture with minutely lobed margin, situated on a slight eleva- 

 tion, but by no means so prominent as in Sepia. On each side 

 are two apertures, the oral and aboral nephridial apertures (Fig. 

 680, a. I. neph., pt. neph.), corresponding to the single pair of 

 Sepia, but not elevated on papillae. Close to each posterior 



1.6 ap 



, (it. neph 



r. anl.os 



cterv 



pi. neph 

 l.visc.ap 



Fig. (580. — Nautilus pompilius, interior of mantle-cavity of a male specimen with the 

 postero-ventral wall reflected, a. I. neph. oral left nephridial aperture; an. anus; cten. 

 ctenidia ; ey. eye ; /. funnel ; I. <$ ap. left reproductive aperture indicated by a bristle passed 

 through it ; 1. rise. ap. left viscero-pericardial aperture; n. s. Needham's sac; pen. penis; 

 pi. neph. aboral left nephridial aperture ; p. os. aboral osphradia ; r. ant. os. right oral osphra- 

 dium ; v. n. visceral nerves. (After Willey.) 



nephridial aperture is an opening — the viscero-pericardial (l.visc.ap., 

 r. vise, ap.) — leading into the pericardial section of the ccelome ; 

 these are not represented in Sepia. In both sexes there are two 

 reproductive ducts, right and left ; but in both the right alone 

 appears to be functional, and the left is much the smaller. The 



