KONGL. SV. VET. AKADEMIENS IIANDL. BAND. 19. N:0 6. 163 



Euomphalus sculptus 18.55. Mac Coy Palseoz. Foss. 299. 



1862. Id. Sil. Foss. Ireland, 14. 



1867. Saltee Siluria 4th Ed. 532, pl. 9 f. 27, pl. 25. f. 2. 



1873. ID. Catal. Cambr., 90, 157. 

 Turbo momus 1850. D'Orb. Prodr., 50. 



Eiwmphalus laittus M. Coy, Sil. Foss. Ireland, 14, pl. 1 fig. 12 belongs possibly also to this species. 



Shell with short or only slightly prominent spire of five ventricose wliorls. The 

 surface is covered b}' numerous, closely set, revolving lines, alternately lai^ge and nar- 

 row, the larger attaining twice the size of the lesser. They are generally so densely 

 packed that there is no space left between them. The transverse lines of growth form 

 on them crescent shaped notches, one for each line. The aperture is circular, the lips 

 are thin and the umbilicus is narrow and open. H. 34 raill., br. 44 mill. 



There are so many transitional forms, connecting this species with the former 

 that it is indeed a necessity to merge them into one and same species. In Siluria, 

 3d Ed. p. 236 Salter says that Eu. sculptus »appears to be only a variety of Eu. 

 funatus». R. Etheridge jr (Ann. Mag. N. H. 5th Ser. vol, 7 p. 31) also inclines to 

 regard both forms as identical, though his opinion that »sculptus» may onlj- be the young 

 condition of Eu. funatus cannot be upheld, as we have specimens of sculptus quite as 

 large as »funatus». Moreover the opercula are not different. I have such from Djup- 

 vik in Eksta and they only slightly differ from that figured on Pl. XVII f. 2.5. The 

 dimensions are in one specimen: height 3 mill., diam. 9 mill. 



The chief distinguishing feature of this Or. sculptum from Or. globosum is the 

 great number of its revolving keels, which in some specimens amount to as many as 

 fifty. Through their proximity or their distance many gradations in sculpture arise. 

 The same is the consequence of the different fineness or coarseness of the transverse 

 strife. In some these stri» are prominent and distantiated, in others fine, perhaps corro- 

 ded, the first coinciding with the presence of distantiated revolving keels, the låter 

 with the narrow and numerous keels. But however dissirailar in sculpture, they all 

 have the same operculum and around the narrow umbilicus there are two elevated 

 keels as in Or. globosum. The more globose shells have a greater number of keels, 

 closely crowded and there is consequently a continuation of frills on the surface. 



In specimens from the same locality the amount of variation, especially in the 

 sculpture of the revolving keels, is very great, nay, even in the same specimen sculp- 

 tured keels alternate with almost smooth ones. But these, especially in the »sculptum» 

 forms, show a very fine and microscopically rainute, transverse ornaraentation, which 

 of course is through corrosion destroyed in exposed localities and thus causing a smooth 

 surface. Of the »sculptum» group there may be thus discerned at least two minor sub- 

 divisions. 



1. The shell has no less than fifty longitudinal keels, but in common with the 

 other varieties a belt near the suture without any revolving keels and in the wide and 

 deep umbilicus, environed by keels. This has been found in the canal near Westöös 

 in Hall, at Fårösund, and in some specimens at Samsugn, Othem. A nearly similar 

 variety occurs in the shale of Djupvik in Eksta and Wisby, with some 25 longitudinal 



