730 



X)()L()GY 



SECT. XII 



means so prominent as in Sepia. On each side are two apertures, 

 the oral and aboral ncphi'idvd apertures (a. L ncplt. <>p.,p. I. nepli. ap., 

 p. T. ncph. ap.\ corresponding to the single pair of Sepia, but not 

 elevated on papillae. Close to each posterior nephridial aperture 

 is an opening the viscero-pericardial (l.visc.ap.,r.visc.ap.) lead- 

 ing into the viscero-pericardial section of the body-cavity ; these 

 are not represented in Sepia. In both sexes there are two repro- 

 ductive ducts, right and left ; but in both the right alone appears 

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

 the right spermiduct of the male (pen.) is situated on a cylindrical 

 prominence the penis placed close to the middle line. In the 

 female the nidamental glands are, as in Sepia, conspicuous objects, 



jbe 



FIG. i.;41. Nautilus pompilius, interior of mantle-cavity of a male specimen with the 

 postern-ventral wall reflected. a.l. /</;/-. aj>. oral left nephridial aperture ; an. anus ; ctoi. 



cteuidia ; 1. <J ap. left reproductive aperture; I. nut. <>x. left oral osphradium ; /. t'isc. ap. 

 left .viscero-pericardial aperture; ,,m,tt. flaps of mantle; pen. penis; p. I. ,</)//. />. aboral 

 left nephridial aperture; /i. /. ,<</'/< <ip. aboral right nephridial aperture; post. ox. aboral 

 osphradia ; /. vise. up. right viscero-pericardial aperture. 



AY hen the mantle-cavity is exposed ; but they are mainly situated 

 on its posterior instead of its anterior wall. 



Enteric Canal. The mouth is surrounded by a peristomial 

 membrane beset with numerous papillae. There is a pair of 

 jaws (Fig. 64*2, jaw) of similar shape to those of Sepia, but much 

 more powerful, and calcified towards the tips. The buccal mass 

 is a large rounded body with thick muscular walls. On the 

 floor of the contained cavity is a large and prominent odontophore 

 (ml nut.} with long and pointed curved teeth. In front of the 

 odontophore is a large bilobed soft prominence, the tongue, (tone/.). 

 Behind the odontophore, between it and the opening of the 

 (esophagus, are one large median and two lateral tongue-like pro- 

 minences beset with papillae ; on the inner surface of the latter 



