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 Reeve, 



Tho fractions show the number of times (or diameters) the figures 

 are reduced, or magnified. 



PLATE I. 



Octopodidce. 



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



2. • {mandibles) 156 



3. Tremoctopus violaceus, <J. Chiaje. Messina 159, 164 



Teuthida. 



4. Sepiola Atlantica, Orb. Atlantic 169 



6. Loligo vulgaris. Lam. {gladius). ^. Britain 167 



7. Onychoteuthis Bartlingii, Le Sueur. \. Lidian Ocean 171 



8. [gladius). \ 171 



Sepiadce. 

 6, Sepia officinalis, L. i. Britain 177 



Spirulidae. 

 9. Spirula laevis. Gray. ^. New Zealand , . , . . 173 



