98 G. LINDSTROM, ON THE SILURIAN GASTROl'onA AND PTKROPODA OF fiOTLANll. 



6. Pleurotomaria glandiformis n. 



PI. VII fig. 37—38. 



Shell elon<i;ak'clly conical, turbinated, with seven convex whorls. The slit band 

 is placed a little above the middle line of the body whorl, relatively more narrow than 

 in the preceding species or nearly half that size. In the other whorls it is situated a 

 little below the supei'ior suture. The bordering lines are not so prominent as in the 

 preceding. The crescents are nearly alike, distantiated, regular, crossed by two or three 

 longitudinal lines. The surface on both sides of the band has a regular, cancellated or- 

 namentation by equal sized lines, which at their crossing point form a little, elevated 

 nodule. Suture deep. Aperture elongate, higher than broad, umbilicus narrow, but 

 open. 



Height 19 mill., breadth 1.5 mill. Aperture in height 8 mill., br. 7 millim. Api- 

 cal angle .56°. 



It has been found in many specimens in the red limestone of Sandarfve kuUe, 

 a few in the gray limestone and also in the neighbouring Linde klint. 



This species is very nearly related to the preceding one, having the slit band 

 formed on almost the same type, but it differs through the ornainentation of the sur- 

 face where small nodules are formed at the crossing point, as well as in the shape of 

 the shell and the whorls, which are angular in the former and evenly rounded in this 

 species. 



7. Pleurotomaria Ibiformis n. 



PI. VII fig. 39—42. 



Shell broadly conical, turbinatecl, with seven tumid whorls, four times as broad as 

 high and having the slit band a little below the middle line of the bodj- whorl and 

 midway between the upper suture and the median, transverse line of the other whorls. It is 

 much concave, forming a shallow groove around the shell, with sharp, elevated borders 

 on both sides. The crescents are fine, narrow, densely packed, more curved than in 

 the others and crossed by numerous, equally fine, longitudinal streaks. As seen by the 

 tig. 42 the ornamentation is widely dissimilar above and beneath the slit band, being 

 imbricate and crossbarred above, and with two different sets of strias below: one con- 

 sisting of coarse, irregular and distantiated transverse wrinkles, in their direction corres- 

 ponding with those above the band, though meeting the slit band in a more acute 

 angle, the other crossing these obliquely, nearly parallel with the slit band. They are 

 microscopically minute and remind of those which cover the whole shell of Pleurot. 

 exquisita. There is besides on the whorls an obtuse ridge beneath the slit band, parallel 

 with it and close above the suture the whorl ends in a somewhat nodular ridge or 

 string. The aperture is nearly circular. The umbilicus is narrow and open, on its distal 

 side enclosed by a low ridge, which emanates from the back of the columellar lip, on 

 its proximal side it is hemmed in by the basis of this lip, which is enlargened as a 

 broad lamella and nearly hides the umbilicus, when seen from above. 



