130 G. LINDSTRÖM, ON TIIE SILQRIAN GAHTUOPODA AND PTEROPODA OF GOTLAND. 



The apex of the spire is in all specimens, which have been investigated, filled 

 up with solid calcareons spar of a brownish colour, without any trace of transverse 

 diaphragmata. The nuclei have a glossy surface and look as if the interiör walls of 

 the shell had been porcellanous. The slit band is prominent a little above the middle 

 of the whorls, it is narrow and slightly concave along its median line- The aperture 

 is rathei" obovate approaching to the circular. The umbilicus seems to have been 

 large and open as shown by longitudinal sections when there is no corapact columella 

 (fig. 18), but an open tubular axis interiorly. 



Very frequent in the inferior limestone of Ostergarn at Grogarn and Katt- 

 haramarsvik, but almost only as nuclei, on which traces of the sculpture of the shell 

 are visible. It has also been found in the neighbourinof strata of Kräklinojbo and 

 Ardre, and it is probable that some nuclei from the limestone of Wisby belong to 

 this species. 



Height 80 millira., breadth 21 mill., apical angle 22 °. 



This common species has usually been confounded with Murch. cingulata, as 

 HisiNGER himself did, till he in his »Förteckning öfver Svenska petrificater», edited 1841, 

 p. 56, separates it from M. cingulata, without giving it any new name. 



7. Murchisonia attenuata Hisinger. 



Pl. XII fig. 20—24. 

 Turbinis marini nucleus lapideus Irevis etc. Bromell Act. Lit. Siiec. 1738 vol. III p. 37. 



Turritella attenuata 1840. His. Leth. Suec. Supplem. Secundum, 4. tab. 37 f. 7. 

 1841. Id. Förteckning, 56. 



1848. Bronn Nomenclator, 1331. 



Murchisonia attenuata 1867. Lindström Nomina foss. Gotl., 23 (nec. Murchisonia attenuata Hall 1856, 



Träns. Albany Instit. vol. IV, 27). 



Shell elongate, whorls seven in the most complete specimens, though there have 

 certainly been many more. The whorls are ventricose, nearly as long as broad, some- 

 what angular where the slit band is projecting. This band is narrow, placed a little 

 below the median line of the body whorl and quite on the middle line of the other 

 whorls. It has an even surface, fig. 24 section, the crescents are regular, fig. 23. 

 But near the aperture in large specimens the transverse ornamental strias above and 

 beneath are confluent with the band without any separating or bordering lines and 

 it continues only as an elevated ridge, sometimes not clearly distinct from the 

 surface. In this feature it shows relations to such genera as Euomphalus and 

 Loxoneraa (for inst. pl. XV fig. 9) and also to Pleurot. planorbis His. The shallow 

 suture crosses the longitudinal axis in a line more oblique than in the other species. 

 There is no umbilicus and the aperture is oblong, the uppermost corner acumi- 

 nated, its columellar lip thin, reflexed. Height 51 millim., width of body whorl 

 18 millim. 



