KONGL. SV. VET. AKADEMIENS HANDL. BAND. |9. N:o 6. 121 



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

 scentic lauiclke oblitpiuly cut, and fig. 22 is a section rectangular to the former. In 

 fig. 21 a magnitied portion of a cloven band is delineated, where in the interior the 

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

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

 distantiated. Above the slit band the transverse stria^ are still finer and more numerous 

 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 shai'p. 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 complete specimens. But this, as well as similar irapi'essions 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 Gnisvard and Westergarn and in north as far as the 

 shale of Halls link. 



35. Pleurotomaria Marklini n. 



PI. XI, f. 24— 2G. 



Shell trochiform, nearly flat on the umbilical side. Whorls six with 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 obliquelj^ 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. 



PI. XI f. 27—29. pi. XII lig. l—o. 



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 coalesced with the surface of the next younger whorl. Tlie ornamenta- 

 tion on both sides of the band consists of gently curved striae, turning backwards from 

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

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



K V.'t. Ak:i.l. Ilniidl Ban.l H1. N:r> li IG 



