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



159 



The variety figured pl. XVII f. 4 is in some way a transitional form to the 

 following. 



2. Oriostoma discors Sow. var. rugosum Sow. 



Pl. XVII fiff. 5—10. 



Delphinula 

 Euomphalus riigosus 



1811. 

 1814. 

 1839. 

 1843. 

 1847. 

 1848. 

 1854. 

 1855. 

 18G7. 

 1871. 

 1873. 

 1814. 

 1818. 

 1828. 

 1829. 

 1831. 

 1831. 

 1837. 

 1840. 

 1858. 

 1867. 

 1876. 

 1883. 



Straparollus rugosus 1850. 

 Strajiarollus catenulatus 1850. 



Euomph. angidosus 

 Helicites catenulatus 



Delphinula catenulata 



Euomphalus catenulatus 



P.^RKi.NSON Org. Rem. III, 77, pl. VI f. 7—8. 



Sow. Min. Conch. I, 113, pl. 52 f. 2. 



Id. Sil. Syst., 626, pl. 12 f. 19. 



Morris C.\tal., 145. 



MuRcmsoN Qu. Journ. Geol. Soc, 29. 



BaoNN Noraenclator, 481. 



Morris Catal. 2d Ed., 248. 



Mac Coy Palteoz. Foss., 298. 



Salxee Siluria, Ed. 4, 532, pl. 24 f. 13. 



Baily Charact. Br. Foss. pl. 21 f. 8. 



Salter Catal. Cambr. Foss. 157. 



SowERBY Min. Conch. vol. I, 114, pl. 52 f. 3. 



Wahlenb. Petref. Suec, 72. 



His. Anteckn. IV, 237. 



Id. Tableau ed. 1, 10. 



Id. Tabl. ed. 2, 8. 



II). Anteckn. V, 114, tab. 1 fig. a. 



Id. Lethpea. 37, tab. XI f. 9. 



lu. Förteokn., 55. 



Fr. ScHMiDT Esthland, 204. 



Lindström Nomina, 23. 



Feru. Eoemer, Letli. Geogn. pl. 14 f. 8. 



Qdenstedt Petrefaktenkunde Deutschlands, le Abth. 7r Bd, 397, pl. 200 f. 90 



(not tig. 91). 

 D'Orb. Prodr. I, 29. 

 Id. Ibid. 30. 



Shell nearly discoidal, spire only a little prominent or turbinated, whorls six, 

 carinated by eight or ten longitudinal keels, interrupted on pretty equal distances by 

 large, sinuous lines of groAvth, which are elevated in a backwards reflexed fold at the 

 point where they meet the keels, giving in their totality an imbricate or roughly scaly 

 appearance to the surface. Between the larger lines, which are niuch distantiated, 

 the surface is sculptured by minute lines, parallel with them. The umbilicus is open 

 and the aperture circular with a continuous peristome of thin lips. H. 37 milL, br. 

 68 mill. The lips of the aperture are much unequal, the exteriör one being prominent, 

 the interiör, deeply insinuated, expecially at its superior corner, the distance between 

 both amounting to 28 millim. in one of the largest specimens. It occurs frequently, 

 though not so common as the former, in Fårö, at Wialmsudd, Samsugn in Othem, 

 Lännaberg in Slite, Möner in Boge, Stor Wede in Follingbo, Martebo, Kålens Qvarn 

 and Galgburget near Wisby, in the shale beds of that town, Östergarn both in the 

 shale and the limestone, Ardre, Bara hill, Linde, Klinteberg and Fröjel. 



The range of variability is very wide within this group. Along with shells of short 

 spire, long spired or turbinate shells occur, and together with those of rare transverse 

 imbrication, there are others which have it dense. The specimens from Östergarn and 

 Klinteberg are commonly almost disciform, those from Samsugn with long spire and 



