

ement, \\hiUt in the 



, ,n, -Hi : in tin- foiim-i the *\<\\<. pt iM- ' 



6 entirely, 1'nHillin- the I'm 

 li| ; uhiUt in tin- latter the litt.-i I i'h 



protection, imt the peia-u- onei are \\ith. .m it. 



I',. Auditory Or<inn*. \\\ tin- dil:-anehiale^ tin- audit" 



: ,iv lodged in cavities of the cephalic cartilage : tli.-\ each 



tain :i -in^le. lar^e. CalcarCOUB Otolite. In the N:mtilu-. i 



these sacks are !'<>nnd attached to ilu- |-l:il -.-in-lia, and 

 numerous otolites. Tlit- external ears are imllmv. |.li-.v 



68 ..n tin- sidr uftlir eyes, coniniiinicatin- tlirn 

 lim-d 1\ a o-landnlar inrinltr.-ni.'. with Mir audit>r\ sacks. 



C. Olfactory o/-,/""*. Killikcr ha> mad.- tl.r interesting dis- 



rv tliat a pair of pits or papilla-, a^ tin- CS8 may be,sittU 



l, ( . hind or above thr eye, are olfactory organs. Th.-x are pit- 



above the eyes in the Tetithida- and Sepiada- and in some "f the 



pods,but in Aro-,,nanta and Tremoctopus they are devel- 

 oped as papilla-, and in Nautilus are elongated liU.- Bmall tentacles, 

 placed immediately behind the eyes. D'Orbignj has mistaken 



them t't.i .-\ternal ears. 



Organsof Respiration, Circulation and >< 



The heart, whirl, is plaeed oil the ha-mal side of the i 



receives the blood through contractile vessels connecting it mth, 

 and equal in Dumber to the branchiae; these max be regard* 



auricles. The branehia- are mt ciliated, and aiv -etierallv il 



always themselves contractile. The arteries end in an . 

 sively developed capillarj system, but the venous chana 



to some extent the elu.raeter of sinuses. In retnrni. 



heart, the venous blood is gathered into the i 



longitudinal sinus, which is situated on the poster* 



body close to the anterior wall of the branchial ehau 



divides into :. Dumber of branchial * ponding iritb 



the number of branchiae. Bach of the* 



chamber in communication with the mantle c 



ln av tx ..... tisidered a renal organ), and that portion whi< 



