KONGh. SV. VET. AKADEMIENS HANDL BAND. 19. N:() 6. 125 



circular witli thin li|)S. Tlic |icristoine is interrupted. 'I'lic iiinbilicu.s is open :ui(] 

 wide, showing all the interior whorls, it is accoiiipiinii'd by a spiral groove near tlie 

 interior border of tlie whorls. 



Height 5 niillim., breadth Hi mill. 



Occurs plentifully in the shale beds of Djiipvik in Kksta and has also been found 

 in a few specimens in the shale of Wisby. 



As to its depressed spire and the position of the slit band this s])ecies resembles 

 very nmch some Devonian Schizostomata figured by Guldfu.ss in liis I'etref. GermaniLC, 

 plate 188 figs 4—6. 



Divisio VIII. NATICOIDE^. 



89. Pleurotomaria exquisita n. 



PI. XI, ligs. 30—33. 



Siiell ovato-globose, naticoid, glossy, with live ventricose whorls, of which the 

 body whorl many times surpasses the others in size. The slit band is situated above 

 the median line of the body whorl and is in the others completely hidden under the 

 covering lower edge of the superjacent whorl. It is comparatively large, on a level 

 with the other surface and enclosed by a tine, distinct line on each side and crossed by 

 irregularly distantiated, linear crescents, which are a little oblique, lig. 32. Some three 

 or four shallow grooves run rectangularly to these along the median line of the band. 

 Tlie transverse lines of growth are bent in curves directed from the aperture back- 

 wards, those above the slit band being more curved than the others. In the opposite 

 direction, obliquely crossing them, almost microscopically minute stria; are seen, on 

 both sides of the slit band, as well as on this band. Those above the slit band do 

 not cross its superior bordering line, but follow it in a highly acute angle, densely 

 packed. They are sinuous and bifurcated. Those on the slit band are in direct con- 

 tinuation Avith those below, which are sinuous without bifurcation, more distantiated 

 and more oblique. The suture is so shallow, that the whorls on both sides of it form 

 m.-arly an even line. The aperture is obliquely elongated, longer than broad, the lips 

 are thin, the inner one reflexed around the umbilicus, which is of moderate size. 



Dimensions: height 9 millim., breadth nearly 10 mm. 



This beautiful little shell, one of the most remarkable through its peculiar orna- 

 mentation, has been found in numerous specimens in the shale beds of Djupvik in 

 Eksta. There is probably also a specimen from the shale of Wisby. 



Gen. MURCHISONIA D'Archiac & Verneuil. 



1841. Murchisonia D'Archiac & Vern. Bull. Soc. Geol. XII p. 154. 

 1859. Ilormoloma Salter Canad. Organ. Remains Dec. I p. 18. 



Shell elongated tiirriculate, wliods numerous, slowly increasing in size, oldest ichorls 

 filled ivith organic deposit of calcareous matter. Slit band and ori^amentation as in Pleu- 

 rotomaria. Nacreous lustre not observed. 



