INVEBTEBEATE PALAEONTOLOGY. 32] 



3. ARRHOGES, Gill)l). 



Shell with expanded lip, merely terminating in a single posterior 

 obtuse lobe-like extension, and having its anterior sinus nearly or quite 

 obsolete; posterior canal very short; anterior canal also short and 

 obtuse. — Rostellaria occidentals, Beck. 



In regard to the value of the last two sections, there will doubtless be 

 different opinions. Some will probably maintain that they ought to be sepa- 

 rated generically from Aporrhais; while others will either retain them as 

 subgenera under the same, or even scarcely regard them as subgenerically 

 distinct. I would be inclined to give them greater importance were it not 

 for the fact that we tind Alipes so closely connected through the Tertiary 

 A. speciosa (=. Strombus speciosus, Schlotheim) with the typical Aporrhais; 

 while, on the other hand, the group Arrhoges seems to be equally connected 

 through the Tertiary A. analoga (— Chenopus analogue, Deshayes), and the 

 section Drepanochilus with Anchura proper of Conrad. 



Many palaeontologists, and, until recently, some conchologists, ranged all 

 such shells under the old genus Rostellaria. It is now well known, however, 

 to all intelligent pakeontologists, and, of course, to conchologists, that Aporrhais 

 is widely removed from the genus Rostellaria by the characters of the 

 animal, as well as by only less strongly-marked differences in the shell. 

 There are several extinct types, however, in regard to the structure of the 

 animals, of which we, of course, know nothing from direct observation, which 

 have shells more nearly like that of Aporrhais. Among these may be men- 

 tioned Alaria, Morris and Lycett, Anchura, Conrad, 1'essarolax, Dicroloma, 

 and Hclicaula.v, Gabb. From Anchura and Dicroloma, however, it is at once 

 distinguished by its well-defined posterior canal, and differently-formed lip ; 

 from Alaria and Tessarolax, it is distinguished by having no varices on the 

 volutions, as well as from the want of a posterior canal in the former, and the 

 callus covering most of the spire in the latter. Hclicaulax has a posterior 

 canal, extending up the spire, but connected with a more spreading and 

 callous inner lip ; while its expanded outer lip has more the character of that 

 of Anchura. 



Aldrovandi has most generally been cited as the author of this genus, 

 but, according to Mr. Gabb and Dr. Stoliczka, incorrectly. I have not had 

 an opportunity to refer to his works ; but both of the last-mentioned authors 

 41 H 



