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



ridges and more finished sculpture than in the former. Also found ut Länsa and 

 Lutterhorn in Fårö, Sändvilc at Fårösund, Klinteberg and the shales of Stora Carlsö. 



2. There is an interinediate variety between this sciilptuin and Or. globosuni from 

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

 Carlsö. 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 iigures of E. funatus, as seen by comparing 

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

 "WERBY låter denominated as Eu. sculptus. The English authors refer to »sculptus» spe- 

 cimens with nuinerous 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. funatus». It is indeed most bewildering to discern in all 

 this mäss 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. 



Fl. XVII lig. 11—16, 18—22. 



Shell large, globular, turbinate, spire short, whorls tive, ventricose, angular throngh 

 the many projecting keels with perpendicular walls between them. On the body whorl 

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

 suture to the highest point of the umbilical side and on that side at least iive. 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 interiör one 

 is short and forms the nearest enclosure of the narrow, spirally wound umbilicus. 

 H. 40 mm. br. 53 mm. 



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

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

 four specimens fi"om Ostergarn as follows: 



1) Diam. 



20 



mm. 



Height 8 mm. 



2) » 



20 



» 



» 10 » 



3) » 



15 



» 



» 6 » 



4) » 



21 



» 



» 6 » 



') SowERBY Miner. Conohol. pl. 450 fig. 1 (the uppermost one) and fig. 2 (but reversed and restored in 

 Lethsea 1. c), 



