LITERATUEE. 95 



ridges on the dorsal side. Animal provided with arins and 

 tentacles of nearly equal length, furnished with a double 

 alternating series of horny hooks, from 20 to 40 pairs on 

 each arm ; mantle free all round ; Jins large, medio-dorsal " 

 (Woodward). Only one species is known, from the Oxford 

 Clay (Middle Oolites). High authorities, such as Owen and 

 D'Orbigny, question the validity of this genus, and regard 

 it as being founded upon specimens of Belemnites. 



cl. XiplioteufJiis. — Guard narrow and cylindrical, containing 

 a very long, deep -chambered, narrow phragmacone. Pro- 

 ostracum greatly developed (nearly a foot in length), very 

 narrow at its base, widening out anteriorly, and finally ter- 

 minating in a pointed apex. Only a single species is known, 

 from the Lias. 



e. In addition to the above, the Cretaceous genus Cono- 

 teuthis and the Jurassic Plesioteuthis are probably really re- 

 ferable to the Belevinitida:. ; and high authorities place here 

 the Tertiary genera Beloptcra and Belemnosis. The Jurassic 

 Acantlioteuthis is founded upon horny hooks, which were 

 probably attached to the suckers of Belemnites. 



LITERATURE. 

 General. 



1. " Manual of the Mollusca." S. P. Woodward. 3d ed., with " Ap- 



pendix of Recent and Fossil Conchological Discoveries," by 

 Ralph Tate. 1875. 



2. " Handbuch der Conchyliologie." Philippi. 1853. 



3. " Malacozoa." Bronn and Keferstein. In ' Bronn's Klassen und 



Ordnungen des Thier-Reichs.' 1862-66. 



4. " Traite elementaire de Conchyliologie." Deshayes. 1839-59. 



5. " Mineral Conchology of Great Britain." J. Sowerby. 1812-30. 



6. " Traite de Paleontologie." Pictet. 1853-57. 



7. " Cours elementaire de Paleontologie." D'Orbigny. 1849-52. 



8. " Materiaux pour la Paleontologie Suisse." Pictet, (Begun in 



1834.) 



9. " Catalogue of British Fossils." Morris. 1854, 



POLYZOA. 



10. " Catalogue of the Marine Polyzoa in the Collection of the British 



Museum." Busk. 1852. 



11. " Monograph of the Fossil Polyzoa of the Crag." Busk. ' Paleeon- 



tographical Society.' 1859. 



