164 G. LINDSTRoM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND. 



ridges and more finished sculpture than in the former. Also found at Lansa and 

 Lutterhorn in Far5, Silndvik at FarSsund, Klinteberg and the shales of Stora Carlso. 



2. There is an intermediate variety between this sculptuin and Or. globosum from 

 Martebo, and from the marly limestone beds above the shales of Eksta and also Lilla 

 Carlso. It has the ridges distant on the apical surface, crowded on the umbilical, thus 

 combining both the funatus and sculptus characters in the same specimen. This has 

 also been found in Martebo, Samsugn, Slite, Medebys in Hall, Sproge and Hoburg. 



Although HisiNGER copied Sowerby's figures of E. funatus, as seen by comparing 

 their figures'), he, in his own collection, partly gave that name to the shell which So- 

 WERBY later denominated as Eu. sculptus. The English authors refer to ))sculptus» spe- 

 cimens with nuuierous crowded keels, but in that number possibly several different 

 species may have been confounded. M'Coy Brit. Pal. Foss. p. 299, says "that the ab- 

 sence of the transverse scale like sculpturing and the . . . more numerous ridges, easily 

 separate this from the E. funatusn. It, is indeed most bewildering to discern in all 

 this mass of similar and yet, as their opercula prove, specifically different forms and 

 mistakes can scarcely not have been avoided in my arrangements of them. 



6. Oriostoma coronatum n. 



PI. XVII fig. 11—16, 18—22. 



Shell large, globular, turbinate, spire short, whorls five, ventricose, angular through 

 the many projecting keels with perpendicular w-alls between them. On the body whorl 

 there may be seen as many as seven or even nine keels on the exterior side from the 

 suture to the highest point of the umbilical side and on that side at least five. Smal- 

 ler keels intervene between them. The large keels are crenated by blunt spines, for- 

 med by regularly distantiated, oblique folds, causing the often ocurring cone in cone 

 structure. Where these folds are perfect, their edges are considerably thin, a little 

 forward bent or generally having the shape of small crescents. The interstices, which 

 are nearly five times as large as the keels, are almost smooth, transversally striated 

 by microscopically minute lines, directed obliquely, or nearly perpendicular, backwards 

 from the suture to the umbilicus. The aperture is circular, the outer lip thin, the in- 

 ner lip thickened, almost reflexed. Around the umbilicus there is a deep and broad 

 groove (fig. 14) bounded by two high and prominent keels, of which the interior one 

 is short and forms the nearest enclosure of the narrow, spirally M^ound umbilicus. 

 H. 40 mm. br. 53 mm. 



The operculum is very frequent and has in some instances been found m situ. 

 It is button shaped, perfectly circular, more or less elevated. The dimensions are in 

 four specimens from Ostergarn as follows: 



1) Diam. 20 mm. 



2) » 2U » 



3) » 15 » 



4) » 21 » 



') SowERBY Miner. Concho!, pi. 450 fig. 1 (the uppermost one) and fig. 2 (but reversed and restored in 

 Lethsea 1. c.), 



