CEPHALOPODA. 361 



gressively contracting, and being pushed, as it were, towards the head ; 

 the short intestine is developed from the bottom of the stomach (b), 

 and passes straight forward to the base of the projecting funnel. The 

 arms grow around the mouth (a) and the vitelline duct, which is 

 continued anterior to the mouth, parallel to the oesophagus, and 

 gradually dilates (J) as it descends into the stomach. The original con- 

 nection of the yolk-bag is in part retained or indicated in the Octopus 

 by the anterior caecal production of the crop. At the later periods of 

 development the respiratory movements are vigorously performed by the 

 alternate dilatation and contraction of the mantle and by a corresponding 

 erection and depression of the funnel : the ink-bag (e) is now con- 

 spicuous by the colour of its contents, which are sufficient to blacken 

 a considerable quantity of water, and the little Cephalopod is thus 

 provided with the means of concealing itself from any enemy that 

 might be prepared to devour it upon its emergence from the defensive 

 covering of the ovum. At the period of exclusion five of the layers 

 of the dorsal shell (/) of the young cuttle-fish have been formed ; 

 but, except the nucleus, which is calcified, they are horny and trans- 

 parent. The lateral fins are not merely developed, but are broader 

 than in the mature animal ; and the cephalic arms are furnished with 

 a web ; so that the young Sepia is enabled to swim either forwards or 

 backwards, and its eyes have acquired the requisite development to 

 warn it of an approaching enemy, or direct its course to its appro- 

 priate food. 



And now, Mr. President, I perceive that the hour of lecture has 

 drav/n to its close, and with it the period allotted for the annual ex- 

 position in this theatre of the physiological treasures of the Hunterian ' 

 Museum. I should do injustice to my feelings were I, Gentlemen, to 

 suppress the expression of the great gratification which your untiring 

 attendance at these lectures has afforded me. This encouragement, 

 knowing that the lectures would commence with the lowest and most 

 minute forms of animal life, and be exclusively devoted to the Inver- 

 tebrated classes, I had not ventured to anticipate from an audience, 

 including many members who are actively engaged and eminent in 

 the practice of an arduous profession. 



For there is so small a part of the multifarious and diversified 

 details of the anatomy and physiology of the Invertebrata, from which 

 the practical Surgeon can directly profit : they seem so remotely 

 connected with human physiology : the animals themselves are so 

 different in form, in powers, in modes of life, from those which 

 more obviously attract the interest of the anatomical Teacher. 



We learn, indeed, with little surprise, that the import of the dissec- 



