30 1MCKSTIVE ORGANS. 



and resembling that of a parrot, within which is a fleshy tongue 

 armed with teeth. These parts are enveloped in a lar^e muscular 

 bulb which supplies the force to the jaws. Kxternal to the l>eak 

 are two li]>s. themselves surrounded and protected by an ex- 

 tensible Ituccal membrane, situated between the buccal bulb and 

 the b;ises of the arms. Whilst the buccal membrane is wanting 

 to the octopods, it, is well marked on the eonlrary in the deca- 

 pods. In development it forms a vast funnel, and in repose it 

 covers all the exterior part of the mouth. It is encircled by 

 eight or ten fleshy appendages, externally marked by as many 

 muscular ridges which correspond to t he bands connected with 

 the arms. The buccal membrane, doubtless assists in retaining 

 the food of the animal in juxtaposition with the mandibles, and 

 for this purpose the fleshy appendages are provided at their 

 internal extremity in the Calamaries and in Sepioteut his with 

 enpules similar to those found on the arms. 



The lips, of which the external one is thin, always short and 

 with entire border, and the internal, in contact wit h the beak, 

 thickened, fleshy and papillary or ciliated upon its eduv. can be 

 contracted over the beak, so as to cover it entirely, fulfilling 

 functions analogous to the lips in mammalia. 



The beak is corneous; with a more or less calcareous invest- 

 ment in the tetrabrauchiates. It differs from the beak of birds 

 in that, the superior mandible instead of covering the inferior,, 

 shuts, within it. The superior mandible is composed of two 

 distinct parts, the one rostral, more or less arcuated, sharp in 

 front, forming behind a hood separated by an Inferior expansion 

 varying in length or breadth according to the nvnus. The 

 inferior mandible, always larger, has a less sharp rostrum, ami 

 is also composed of a rostral portion and an inferior expansion ; 

 but with this difference, that the lateral part is elongated on each 

 side and forms a winLT. varying in form. 



Calcareous in Nautilus, llhyiichoteiif his and I'alcoteut his. the 

 beak is infinitely larger, -without hood in I'aleoteut his. whilst 

 alonn- with the hood there are wide calcareous win^s in Uhynco- 

 teiithis. In the Corneous-beaked species the superior mandible 

 has a very short rostral portion but- little separated from the 

 expansion in Oetnpu^: still but little separated but wirier in the 

 and I'hiloiiexis ( Trenmel opus) ; very lon^. but lillle 



