474 Mr. R. Etheridge, Jun., on the Gasteropoda 



pass in review those species represented on pi. xiii. of the 

 above work. Notes on the specimens of Gasteropoda illus- 

 trated by pis. xiv.-xvi. will be given in subsequent commu- 

 nications. 



The Species figueed on Plate XIII. of Vol. II., ' Geo- 

 logy of Yorkshire/ by John Phillips, F.R.S., F.G-.S. 



1. Euomphalus pentangulatus , Sowerby (Phillips, p. 225, 

 t. 13. fig. 13). 



This, by far the handsomest species of the genus Euom- 

 jphalus, is well represented in Gilbertson's collection. The 

 section figured in the above plate exemplifies in a parti- 

 cularly well-marked manner the peculiar septation and divi- 

 sion into chambers which takes place in the older whorls 

 of this species. With the view of studying this subject more 

 fully, I have had a number of sections of various species made, 

 and hope to speak on this subject at some future date. E. 

 pentangulatus has been described in detail by Profs, de 

 Koninck and M'Coy, and need not be again redefined. From 

 E. catillus the present species is distinguished by its more 

 convex back, more prominent whorls on the non-umbilicated 

 sides, and by the very much less marked character of the 

 ridge bounding the umbilicus as compared with that on the 

 upperside of the shell. The manifest dissimilarity to E. 

 calyx is at once apparent. I quite agree with Prof. M'Coy 

 in considering the form established by Col. Portlock as E. 

 Bronni only a variety of E. pentangulatus , in which the 

 spire is elevated to a more or less greater degree above the 

 keeled edge of the last whorl. The Gilbertson collection 

 contains specimens of this variety. The present species is 

 the 



E. pentangulatus, J. Sowerby, Min. Conch. 1814, i. p. 97, t. 45 (2 



upper figures). 

 iSkeriea perangulatus, Fleming, Brit. Animals, 1828, p. 314. 

 E. pentangulatus, Bronn, Lethsea Geogn. 1885, i. p. 94, t. 2. fig. 2, a, b. 

 E. pentangulatus, Phillips (as above). 

 Schizostoma catillus, Fischer, Oryct. Gouv. Moscou, 1837, p. 129, t. 49. 



figs. 3, 4. 

 E. Bronni, Portlock, Geol. Rep. Londond. 1843, p. 417. 

 E. quinquangulatus, Goldfuss, Petref. Germ. pt. 3, p. 87, t. 191. 



fig. 3, a-c. 

 E. pentangulatus, M'Coy, Synop. Carb. Limest. Foss. 1844, p. 37; Bronn, 



Index Pal. Nomen. 1848, p. 480; Brown, Foss. Conchol. 1849, p. 81, 



t. 42. figs. 28, 29 ; M'Coy, Brit. Pal. Foss. 1853, fasc. 3, p. 540 ; 



Morris, Cat. Brit. Foss. 1854, ed. 2, p. 248. 

 E. quinquangulatus, Eichwald, Lethaea Rossica, 1860, i. pt. 2, p. 1153. 

 E. pentangulatus, Rorner, Lethsea Geogn. Atlas, 1876, t. 45. fig. 10, 



