DIGESTIVE ORGANS. 31 



separated in the Calamaries, in Sepia and Sepiola ; less long but 

 well separated in Ommastrephes ; but little separated in Onycho- 

 fceuthis, in Loligopsis and in Histipteuthis, which at the same 

 time have a mueli longer, more curved and sharper rostrum. The 

 posterior expansion is short, composed of three equal lobes in 

 the Argonauts and Tremoetopus, very long and with only an 

 indication of a lobe in Octopus, and without lobes in Sepia, the 

 Calamaries. Rossia and all other cephalopoda. 



The rostral part of the inferior mandible is rounded behind in 

 all the octopods, slanting in the decapods. The wings are short, 

 wide in Argonaula and Tremoetopus; very long, narrow and 

 arcuated in Octopus'; long, straight and wide in Sepia, etc.; 

 short in Onyehoteuthis and Ommastrephes. The posterior ex 

 pansion is wide, not carinated above in Argonauta and Trcm 

 octopus; very long, narrow, carinated in Octopus; moderatch 

 long, wide, carinated above, more sloped in Sepia, Scpiola and 

 the Calamaries; very short much carinated, strongly sloped IK- 

 hind in Onyehoteuthis, Ommastrephes, etc. 



ruder the tongue is found a lleshy mass covered with papilla 

 which is supposed to be the organ of taste ; and in .Nautilus w> 

 find similar papilla.' on the tongue (behind the teeth), to if 

 entrance into the gullet. 



The lleshy tongue is armed 'above with rows of recurved, 

 spinous teeth, the arrangement of which dillers in the various 

 genera. Ordinarily, as in the dibranchiates, we lind the series 

 of teeth to consist each of a central one with three side-teeth oil 

 either side of it, and sometimes, as in Kledoue and Loligo, an 

 additional plate on either side; but in Nautilus we find a modi- 

 fication,, in live somewhat quadrangular central teeth of which the 

 middle one has the most pointed end, and on either side two 

 long fan^s with a much smaller plate at the ba~se of each in all 

 thirteen teeth in a series. The central teeth, which are simple in 

 Sepia and Sepiola, arc tricuspid in Loligo and denticulated in 

 Eledone ; whilst the lateral unrini are .usually claw-like. Fifty 

 rows of teeth may be found on the tongue of the Sepia ; their 

 continuous growth compensates the loss by abrasion. 



( Hales f> and C> exhibit the teeth of various cephalopoda.) 



The rounded, sack-like stomach which is situated towards the 

 middle or end of the body is connected with the mouth by a long 



