XII 



PHYLUM MOLLUSCA 



7:;:. 



op 



op 





eff.vess 



* 



post aorl 



humour, nor iris. The sea-water, passing in through the central 

 aperture, directly bathes the 

 retina, which is spread over 

 the interior in a thick layer. 

 Reproductive Organs. 

 The testis (Fig. 644, test.) 

 or ovary (Fig. 645, or.}, like 

 that of Sepia, is single and 

 median, enclosed in a special 

 sac towards the aboral end 

 of the body. The ducts are 

 paired in both sexes, but in 

 both the right alone appears 

 to be functional. In the 

 male a large glandular vesi- 

 cula seminalis, in which the 

 spermatophores are formed 

 (ace.} is connected with the 



. , ' , 1,1- l''i'" ''44. Nautilus pompilius. iuul< ix-pm- 



Flght dUCt, and thlS appears ductive organs, ace. vesicula semiiaJis ; e^. rm. 



to VIP T-Piirpsprifprl 'm tlip efferent branchial vessels ;l.,,e-,i. op. left .genital 



- ~l' L opening ; post MO. posterior aorta ; pi/,: pyriform 



left-hand side by a Vestige appendage; r.ffen. op. right genital opei.; 



/ x/i. x. spermatopnore sac; tut. testis ; 



the so-called pynjorm sr ventrick-. 



(pyr.), situated close to the 



ventricle. The distal part of the right duct dilates to form a 

 receptacle, the spermatophoral sac (sp. s.), and opens, nearly in 



the middle line at 

 7-.pe-n.op tne en( j O f a p ro . 



l.(?TL.op minence the penis 

 (Fig. 641, pen.}. In 

 the female the right 

 oviduct has a glandu- 

 lar dilatation, which 

 is supposed to be 

 an albumen gland 

 The ova are of large 

 size, greatly exceed- 

 ing those of Sepia 

 in dimensions, con- 

 taining a large pro- 

 portion of food-yolk. 

 X i ( lamental glands 

 are present, but are 

 mainly situated on 

 tlie posterior, instead 



Fi<;. 045. Nautilus pompilius, female reproductive ( ,f f]i,> antei'lOl', 



organs, a/ii. albumen' gland ; Z. ^eri. o#. left genital open- j, , , , 



ing; or. ovary ; jim: pjTifonn appendage ; r. ffi ,>. op. right Wall 01 tl!6 lliailtlc- 



geuital opening ;" rent, ventricle. (After Lankester and 

 Bom-ue.) 



