7(iO 



ZOOLOGY 



SECT. 



less completely united in the middle so as to form a transverse 

 ridge ; these are the aboral osphradia (p. os.). In the middle line 

 of the mantle-cavity is the anus (an.), a large aperture with minutely 

 lobed margin, situated on a slight elevation, but by no means so 

 prominent as in Sepia. On each side are two apertures, the oral 



pl.neph 



L.ULSC.i 



FIG. OH!>. Nautilus pompilius, iuterior'of mantle-cavity' of a male specimen with the 

 postern-ventral wall reflected, a. 1. ncjth. oral left renal aperture ; an. amis ; ctcn. ctenidia ; 

 en. eye ;/. funnel ; 1. <J ap. left reproductive aperture indicated by a bristle passed through 

 it ; /* me. ap. left viscero-perieardial aperture ; n. *. Needham's sac : /. penis : jii. ./<//. 

 aboral left renal aperture : />. x. aboral osphradia : /'. ant. OS. riirht oral nspftradium ; v. 11 . 



visceral nerves. (After Willey.) 



and aboral renal apertures (Fig. 689, a. I. H<'/>/I.. j>t. nc/>//.), corn- 

 spending to the single pair of Sepia, but not elevated on papillae. 

 Close to each posterior renal aperture is an opening the visccro- 

 pericardial (I. vise, ap., r. vise, ap.) leading into the pericardia I 

 section of the coelome ; these are not represented in Sepia. In 

 both sexes there are two reproductive ducts, right and left ; but 



