PLATE XI. 



Figure i. 



Diagram of Cephalopod, from V. Carus' Tcones Zootomicae, p. iii., fig. 30- 



The following points, characteristic of the class, are embodied in 

 this figure ; the formation of ' arms/ a, by the division and elonga- 

 tion of the margins of the ' foot'' proper; the formation of a funnel, 

 f, by the coalescence of the epipodia ; the relations of the mantle, b, 

 to the funnel, branchiae, and anus ; the presence of a cephalic carti- 

 lage, of highly-developed eyes, and of a digestive canal which, though 

 provided with accessory organs not shown here, is never, in this 

 class, complexly convoluted. 



a. The arms, which in the more highly organized Dibranchiate 



subdivision of the class are provided with suckers. 



b. The mantle, which not only protects the branchiae, and brings 



them into relation with the aerating medium, but also whilst 

 doing so, by its contracting and expelling the water from its 

 cavity through the funnel f, enables the creature to swim 

 backwards. 



c. Eyes, sessile, as in the Dibranchiata. 



d. Auditory vesicle, contained, together with the main nerve 



centres, in a cartilaginous capsule. 



e. Intestinal tract, not forming complex convolutions. 



f. Funnel formed by the coalescence of the epij)odia posteriorly to 

 the 'foot"" proper, which here takes the shape of 'arms' at a. 

 Below the funnel are seen the gills, and between them and 

 the rectum one of the inter-viscerally placed ganglia, which 

 are so abundantly developed in this class. 



For a figure giving full details of the anatomy of a Cephalopod, 

 Octopus Vul(jaris, see Milne Edwards, Ann. Sci. Nat., Ser. iii., 

 tom, iii., pi. 13, p. 341 ; or in Regne Animal ; or in Victor 

 Carus' Icones Zootomicae, tab. xxiii. 6. 



For the nervous system in Cephalopoda, see Hancock, Ann. and 

 Mag. Nat. Hist., 1852, Ser, ii., vol.i., pp. i-14. 



