KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 1"21 



of the others in this group. Fig. 23 represents it sectioned across with some ten cre- 

 seentic lainellaä obliquely cut, and fig. '22 is a section rectangular to the former. In 

 fig. 21 a magnified portion of a cloven band is delineated, where in the interiör the 

 elongated, crescentic lamella^ are directed obliquely, diverging outwards. The whorls are 

 beneath the slit band rounded and covered by fine, threadlike, elevated striaj, equally 

 distantiated. Above the slit band the transverse stria^ are still finer and rnore nuinerous 

 and a little sinuous. The stria^ are directed towards the aperture till they reach the 

 slit band lamina, on which they turn backwards. The aperture is transversally ovate, 

 almost twice as broad as high and the lips thin and sharp. The umbilicus is open 

 and measures nearly a third part of the diameter. Some specimens still retain the 

 nacreous lustre very vividly on the nucleus. A nucleus, fig. 20, shows traces of a ridge 

 around the umbilicus, which, however, has not been observed on the outside of the 

 more cornplete specimens. But this, as well as similar impressions on the inferior 

 surface of the whorls may be due to the crushing of the specimen. Height 20 

 millim., breadth 28 mill., breadth of the umbilicus 9 mill. in a shell having 25 

 millim. in a transverse line. 



Found in the shale and limestone in the vicinity of Wisby, and also in south 

 along the coast in the shale at Gnisvärd and Westergarn and in north as far as the 

 shale of Halls huk. 



35. Pleurotomaria Marklini n. 



Pl. XI, f. 24—26. 



Shell trochiform, nearly flat on the umbilical side. Whorls six Avith even sides. 

 Slit band placed a little above the median line of the whorls, thin and folded in ir- 

 regular wavy curves. The sculpture consists in transverse, oblique lines, which on the 

 umbilical side are coarse, callous ridges. Aperture obliquely ovate, umbilicus open, 

 but narrow. Height 14 mill., br. 18 millim, aperture in height 6 mill., breadth 7 mill. 



Three specimens have been found in the limestone of Klinteberg and the figured 

 one is from the Marklinian Collection in Upsala. 



36. Pleurotomaria cirrliosa n. 



Pl. XI f. 27—29. pl. XII fig. 1—3. 



Shell large, trochiform, nearly flat on the umbilical side, whorls seven, modera- 

 tely convex. Slit band situated a little above the median line of the whorls, forming 

 an extremely thin lamina with narrow edge. It is folded regularly and transversally 

 by grooves parallel with the transverse stria? and in the older whorls its broken 

 margins have coälesced with the surface of the next younger whorl. The ornamenta- 

 tion on both sides of the band consists of gently curved stria^, turniiig backwards from 

 the aperture and meeting in an acute angle at the slit band. The interstices between 

 the strite are crossed by short, irregular, unconnected lines between which the surface 



K. Vet. Akad. Ilandl. Band 19. N:o « 16 



