KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 19. N:0 6. 137 



creates a section of it in Solariuin, comprising all the three, first original species of 

 SowERBY. The låter species, viz. E. discors, rugosus and funatus he says belong to 

 Turbo, and others again to Delphinula. He then quite rightly distinguished the true 

 Euomphali from the others and in all probability assigned to the E. discors etc. their 

 true place. 



In the same work he in 1832^) identifies Straparolus of Montfort with Euom- 

 phalus or Solarium. As the confusion in this respect has originated with him and as 

 most of the låter authors have participated his views, it may be as well, here at once 

 to try to clear up this matter. Montfort established, as is well known, his genus Stra- 

 parolus^) in 1810, taking Str. Dionysii as the typical species. On comparing speci- 

 raens of this shell with specimens of E. pentangulatus or E. catillus it must, however, 

 be evident that they cannot possibly be regarded as of the same genus. In Straparo- 

 lus the shell has rounded, tubular whorls without the least trace of ridges, only with 

 some faint, longitudinal stripes and the transverse strias are not angular, as in Euom- 

 phalus, in Euomphalus again the whorls are angular and provided with the distinctive 

 ridge on the apical side. It is, moreover, highly questionable whether Straparolus is 

 identical with those Silurian shells which formerly were confounded with Euomphalus, 

 as E. discors etc. These have in the present memoir, in consequence of the nacreous 

 structure of the shell and the characteristic opercula been placed amongst the Turbi- 

 nidfe and in the genus Oriostoma. No opercula have ever been found belonging either 

 to Euomphalus sensu strict. or to Straparolus nor are they nacreous. If it steadily is 

 kept in view that Straparolus not at all is identical with Euomphalus s. str. and scar- 

 cely with Oriostoma, a great deal of difRculties will be overcome. 



A change is made in 1833 ') by Deshayes thus far that he creates a new genus 

 Bifrontia and in this he ranges E. catillus, while the other two species are left with 

 Solarium as before. It cannot be denied, that there is a certain resemblance between 

 such shells as the Gotlandic E. tuba and Deshayes' Bifrontia ammonoides and B. 

 Deshayesii'') and likewise amongst recent shells, Oraalaxis (Bifrontia) supranitida Wood 

 has a shape that reminds of that of the palaäozoic. 



In his last great work ") he maintains Euomphalus as a genus distinct from So- 

 larium, though belonging to the same family. He is further (1. c. p. 678) willing to 

 accept Bronn's Schizostoma for E. catillus. As to the last mentioned genus, established 

 with E. catillus as type, it was rejected by Ferd. Roemer"), who regards the indented 

 curvature of the aperture too insignificant as a generic character. It may, however, 

 be questioned whether this genus ought not to be retained for such Devonian species 



1) Vol. III p. 986. 



^) Conchyliologie System. II, 174. 



^) Description des Coquilles foss. des Environs de Paris II p. 221. This wovk is dated 1824 on llie title 



page, biit it was publislicd in small parts and it lasted till 1839 before it was completed. According 



to Hermannsen Iiulic. Genernm, Bifrontia was published in 1833. 

 *) Anim. sans vertébres dans le Bassin de Paris, II pl. 26 f. 22 — 28. 

 ^) Anim. sans vertébv. dans le basin de Paris. Vol. II, 660. 

 «) Leth. Geogn. 3:e Aufl. 1 Bd, 456. 



K. St. Vet.-Akad. Handl. Bd. 19. K:o 6. 18 



