132 G. LINDSTKOM, ON THK SILURIAN GASTHOPODA AND FTKKOPODA OF GOTLAND. 



bilicus is visible and the aperture is ovate. Height 21 iiiillim., breadth 12 iiiilliin. 

 Apical angle 38 °. 



It has been found in the coralliferous limestone of Lindeklint and Sandarfve 

 kulle, one specimen from each locality. 



10. Murchisonia munda n. 



PI. XIII fig. 6. 



Shell turriculate, terete, with eight short, ventricose whorls, twice as liroad as 

 high. The narrow, rupelike slit band forms a proiuineiit angle a little below the 

 median line of tlie body whorl and a little above the same line in the other whorls. 

 It is hemmed in by two distinct lines and its surface is prominent and ccjiivcx, the 

 crescents are distantiated, smooth, lamellar and imbricated, quite as in that gr(jup of 

 the Pluurotomaria>, which has been called Crispaj. In this feature the four first species 

 of tlie Murchisuniie oriiatte are similar. Above the band, and parallel with it, a small 

 ridge runs on the body whorl. The surface is transversally striated by gently undula- 

 ting, lamellar, densely placed lines, imbricated as it were. For the rest the shell is 

 quite smooth without any longitudinal or transverse striai. The aperture is nearly 

 obli(juely elliptic and the columellar lip thin and reflexcd, hiding the umbilicus. 



Height nearly 6 millim., breadth 3 millim. 



A few specimens found in the marly strata of the upper limestone of Slite. 



It comes near to the preceding species as to the ornamentation, though this is 

 much iiner in M. munda. 



11. Murchisonia tortuosa n. 



PI. XIII fig. 4, 5, 13, 14. 



Shell turriculate, of nine ventricose whorls, nearly twice as broad as high, an- 

 gulated a little below the middle of the whorls, where the chordlike slit band is 

 placed. This band is narrow, convex and outstanding, composed of nearly tubular and 

 lamellar crescents, wliich cover each other successively, in an imbi'icating way. The 

 lowest part of the whorls is abruptly bent in towards the suture in a face, whereby 

 the suture is uncommonly deep. There is a low ridge between the slit band and 

 the umbilicus parallel with the former. In one specimen, fig. 13 there are also two 

 or three low ridges on both sides of the slit band. The ornamentation consists for the 

 rest in transverse, sinuous, lamellar stria). On the umbilical part there is also much 

 variation, in some a succession of concentric ridges, cut by striic, which are sinuous, 

 as in fig. 14, or in others, as in fig. 5, only transverse stria; and concentric ones near 

 the edges. H. 11 mm., br- 6 mill. 



The aperture is ovate, the inner lip reflexed and hiding the umbilicus. 



J 



