100 G. LINDSTRÖM, ON TllE SILUKIAN GAHTKOPODA AND PTEKOPODA OF GOTLAND. 



A siugle spcciineii fouiid in thc limestone at Saiiisugn in Otheni. The form of 

 the slit band and thé scnlpture of tlie sui-face unite it with the »Multicarinatiu» and 

 especially with Pl. scutulata from which it is distinguished thi"ough the different slit 

 band. 



10. Pleurotomaria Holmi n. 



Pl. XIX fig. 18—20. 



Shell conical, tnrbinated with sevun ventricose whorls, body whorl of the same 

 size as the others taken together, all nearly thrice as broad as high. The slit band 

 is situated a little below the median line of the body whorl and exactly on the me- 

 dian line of the otiier whorls. It is large, projecting, with convex surface. As far as 

 can be made out on the much corroded band, the erescents are regular and distan- 

 tiated. The ornamentation on both sides consists in thin, exert, transverse and longi- 

 tudinal lines, closely set, forming a dense network with indistinet nodules at the Cros- 

 sing point. The transverse lines have a sigmoid direction and are regularly curved 

 backwards close to the slit band. Below the slit band there is a sharpedged ridge 

 near the suture and above that band a slight bulging out of the surface as a callosity 

 is seen in some speciraens. The aperture is circular, and the umbilicus is narrow. H. 15 

 mill., br. 12 mill. 



A few specimens have been found in the middle limestone near Wisby. From 

 the limestone at Slite a small shell (Pl. XIX f. 17) has been obtained nearly resemb- 

 ling the former as to its shape and the prominent slit band. This is, however, placed 

 exactly on the median line of the body whorl and the ornamentation seems to consist 

 only of transverse stria3. H. 5 milh, br. 5 mill. 



11. Pleurotomaria Wisby ensis n. 



Pl. XVIII fig. 50—51. 



Shell rather depressedly conical, tnrbinated, with six ventricose whorls separated 

 by a shallow suture, the apex obtuse and spire short of five whorls, together smaller 

 than the body whorl. The slit band is placed somewhat above the middle line of the 

 body whorl and is hidden from view in the smaller whorls. It is prominent and con- 

 vex as to its surface. The ornamentation below the slit band is of the common reti- 

 culate crossbar pattern, the longitudinal lines being stronger than the transverse ones. 

 The same sort of sculpture seems to have occupied the umbilical surface, but is mostly 

 effaced. The aperture is circular with thin lips. The umbilicus is deep and wide, and 

 defined through a sharp, abrupt edge. H. 10 mill. br. 10 mm. Largest speciraen from 

 Samsugn has h. 15 mm., br. 13 mm. 



Four specimens have been found in the superior limestone on Kyrkberget in 

 Wisby and one in the quarries of Samsugn in Othem. It is only in consequence of 

 it is 1'eticulate sculpture this shell has been placed with the Multicarinata;, and its posi- 

 tion must be afffirmed through the iind of more complete specimens. 



