EXPLANATION OF THE PLATES. 



The principal specimens figured were kindly communicated by Mrs. J. 

 E. Gray, Mr. Hugh Cuming, Major W. E. Baker, Mr. Laidlay of Cal- 

 cutta, Mr. Pickering, Sir Charles Lyell, Mr. Sylvanus Hanley, Prof. 

 James Tennant, and Mr. Lovell Eeeve. 



The fi-actions show the number of times (or diameters) the figures 

 are reduced, or magnified. 



PLATE I. 



Octo2)odida. 



Page 



1. Octopus tubcrculatus, Bl. \. Mediterranean , . . . 163 



2. {mandibles) 156 



3. Tremoctopus -\dolaceus, <J. Chiaje. Messina 159, 164 



Teuthida. 



4. Sepiola Atlantica, Orb. Atlantic 169 



6. Loligo vulgaris, Lam. {gladius). \. Britain 167 



7. Onychotcuthis Bartlingii, Le Sueur, h Indian Ocean 171 



8. {gladius). i -171 



Scjyiadce. 

 0. Sepia officinalis, L. -i • Britain 177 



Spindidcv. 

 9. Spirula lie vis, Gray. -}. Xew Zealand 178 



