104 STROMBID.E. 



thickened, and 2-3 digitated, the digitations continued as carinae 

 on the back of the shell. A. pes-pelecani, Lam. 4 recent species, 

 N. Atlantic Ocean ; fossil, Jurassic . 



Section I. APORRHAIS (sensu stricto). Lip bi- or tri-digitate, 

 posterior digitation canaliform, running up the spire, the ex- 

 tremity free. 



Section II. ARRHOGES, Gabb, 1868. Shell with expanded, 

 simple lip, with a posterior, obtuse, lobe-like extension, the 

 anterior sinus nearly obsolete : anterior canal short and obtuse ; 

 posterior canal very short. A. occidentalis, Beck. 



Section III. GONIOCHILA, Gabb, 1868 (Alipes, Conrad, 1865, 

 without description). Eocene. S. and S. Conch., ii, 193, t. 60, 

 f. 82. 



Section IV. CERATOSIPHON, Gill, 1870. Cretaceous. S. and 

 S. Conch., ii, 196, t. 60, f. 94. 



Section V. CYPHOSOLENUS, Piette. 1876. Jurassic. L. c., ii, 

 193. 



Section VI. TESSAROLAX, Gabb, 1864. Cretaceous. L. c., ii, 

 195, t. 60, f. 89. 



Section VII. PTEROCERELLA, Meek. Cretaceous. L. c.,ii, 195, 

 t. 60, f. 90. 



Section VIII. LISPODESTHES, White, 1875. Cretaceous. L. c., 

 ii, 194, t. 60, f. 86. 



Section IX. HELICAULAX, Gabb, 1868. Cretaceous. L. c., ii, 

 194, t, 60, f. 85. 



Section X. DIMORPHOSOMA, Gardner, 1875. Cretaceous. L. c., 

 ii, 194. 



Section XI. MONOCYPHUS, Piette, 1876. Lip palmated, widely 

 separated from the spire and canal, with an anterior sinus ; 

 anterior canal short. Jurassic. A. camellus, Piette. (Brachy- 

 stoma, Gardner, 1876, appears to be founded on an imperfect 

 Apon hais, having a very long spire. B. angulare, Seeley. Gault). 



Genus DIARTEMA, Piette, 1864. 



Shell Ranelliform, with continuous varices on each side of the 

 spire; lip thick, dilated with a simple or slightly undulating 

 margin, and a slight anterior sinus ; anterior canal short, straight, 

 posterior canal small. Jurassic. 



