KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 173 



14. Orio stoma lineatum n. 



PI. XX fig. 42—44. 



Shell discoid or nearly so, with short spire of five ventricose whorls. The suture 

 is deep and the surface is uniformly lineated by thread fine, elevated, narrow, longi- 

 tudinal ridges continuing without interruption from near the suture to the upper mar- 

 gin of the umbilicus. They are a little larger and more distantiated on the rounded, middle 

 line of the shell. The interstices between them are nearly smooth and the transverse 

 lines which cross them are straight and minute, only in the umbilical opening they 

 are more prominent. The aperture is circular with thin lips and the inner one clo- 

 sely moulded to the preceding whorls, the umbilicus is wider than in any of the other 

 species, with all whorls visible. H. 16 mill., br. 44 mill. 



In the Pala}ontological State Museum of Stockholm twelve specimens are preser- 

 ved, all from the limestone of Klinteberg, and four from the uppermost limestone of 

 Frojel. From the limestone beds nearest above the oolite in Wamlingbo I have ob- 

 tained a fragmentary Oriostoma, which somewhat resembles the preceding. The trans- 

 verse striae are wavy and coarse, and there seems to be a deep groove along the su- 

 ture on the apical side. It forms probably a new species. 



15. Oriostoma nitidissimum n. 



PI. XXI fig. 4—10. 



Shell small, disciform, apex on a level with the outer whorls; five whorls in all, 

 eveidy rounded without any keels or longitudinal striation at all. They are transver- 

 sally and most finely striated by straight lines, running to the open umbilicus. The 

 suture is shallow. The aperture circular and the lips thin. H. 3 mill., br. 8 mill. 



It is very common in the red limestone of the hills of Sandarfve and Linde and 

 a few specimens also from the gray limestone. A shell occurring in the limestone of 

 Stor Wede in FoUingbo is probably only a variety of this. It is more ventricose in 

 the body whorl, the umbilicus is more narrow, and the perpendicular striation is not 

 so dense as in the other form. 



16. Oriostoma dispar n. 



PI. XXI fig. 11—14. 



Shell planorbiform, low on the apical side as well as on the umbilical one and 

 excavated on both sides. Whorls five and a half, rounded on the apical side, flatte- 

 ned on the umbilical one and there provided with a prominent keel in the margin. 

 The transverse strite are distantiated on the umbilical side, finer on the apical side, 

 and directed at first backwards near the suture, then straight down, past the keel and 

 on the umbilical side forwards. The apertui-e is nearly circular, a little angular through 

 the outgoing keels. H. 2 mill., br. 7 mill. A single specimen has been found in the 

 limestone of Follingbo. 



