﻿DALL] REVIEW OF FROG-SHELLS \M> TRITONS 135 



The characteristics of this group have been already referred to at 

 length in the text. The operculum is ovate, with a concentric, later- 

 ally subapical nucleus. 



This completes the list of groups properly belonging to the Sep- 

 tidce. There still remains, however, a group which for many years 

 has been regarded as a genus of the Triton family, but which now 

 appears to form a family of its own, related not to the Tritons and 

 Frog-shells, but perhaps most nearly to the rhachiglossate genus 

 Triton id ca. The type of the principal genus of this group has not 

 yet been anatomically examined, but species of two apparently 

 closely related sections, Monostiolum and Maculotriton, have been 

 examined by the writer and by Messrs. Pilsbrv and Vanatta, 1 and 

 prove rhachiglossate. Since the history of both groups is practically 

 intertwined from the time of their first recognition, both are included 

 here, as well as in the synonymic history with which this article 

 concludes. 



Family COLUBRARIID/E 



Genus COLUBRARIA Schumacher, 1817 



Type Buccinum maculosum Chemnitz. Recent. Synonyms: 

 Colubraria Schumacher, Fischer, Harris, Dall, Cossmann, not 

 Jousseaume, 1881 ; + Epidromus Morch, 1852, H. and A. Adams, 

 1853 ; + Cumia Bivona, 1838. 



Hilda Hoernes, 1884, from the Miocene, has been referred to this 

 group as a subgenus by Fischer, but is regarded as a full genus by 

 Cossmann, from whose figures I should be inclined to regard it as a 

 precursor and near relative of Lampusia with only a terminal varix. 

 I have not seen specimens and therefore hesitate to assign it a definite 

 systematic rank, but feel quite sure it should not be united with Colu- 

 braria, notwithstanding part of the latter genus is restricted to a 

 single varix. 



The genus Colubraria is naturally divisible into several sections 

 or groups. 



Section Colubraria s. s. 



Type Mures maculosus Gmelin, 1792. India. 

 Solid, heavy shells with elevated spire, appressed sutures, numer- 

 ous irregularly disposed prominent rib-like varices, a short recurved 



1 The paper by Mr. Pilsbry in which he suggests that Colubraria may prove 

 rhachiglossate and notes that he and Mr. Vanatta had found Triton bracteatus 

 Hinds and T. decapitatus Reeve to be so, was received by me only after this 

 paper had been sent to the printer, and it gives me much pleasure to confirm 

 his surmise as far as that may be done by a determination of the rhachiglossate 

 character of "Epidromus" szvifti Tryon. 



