1 12 C. LINDSTKOM, ON THE SILURIAN GASTROPODA AND I'TERUPODA OF GOTLAND. 



Delpliinula aiqiiilatcva 1829. Hisinoer Tableau Ed. 1, 10, 



1S:)1. Id. Tableau Ed. 2, 8. 



lS.il. Ii). Antockn. .5, 113. 



Eiitii)iiili(ilii!s lei/Hilaleruti lSo7. In. Letli.xa, 36, tab. XI f. 8. 



1811. lu. Fnrteckning, 5.5. 



I'le.avotomarla (Kijuilaterd 1848. Biionn Nomenclator, 1012. 



Slvnparollus cequilaterxis 1850. D'Orbigny Prodr. I, 29. 



Shell globular or disciform, with short spire of seven Avhorls, resembling those 

 of an Helix. The slit band is only a little below the middle of the body wliorl, and 

 close to the suture, near the upper border of the other whorls. It is narrow and open 

 for a long wa}- from the aperture on the body whorl. Its surface is even and the 

 bordering lines are lamellar, projecting. No definite sculpture is discernible owing to 

 its considerable narrowness. The surface of the shell is sculptured with line, recurved 

 transversal lines. The whorls are somewhat flattened below the slit band, rounded on 

 the umbilical surface. The aperture is transversally oval, the umbilicus wide, and all 

 whorls visible. Diameter 4.') millim., height 20 millim. 



Occurs in the shale beds (a) at Wisby, in the limestone of Sainsugn in Othem, 

 Stor Wede at Follingbo, Wcstoos in Hall, Kyrkberget of Wisby, Kalens Qvarn near 

 Wisby, the hill of Bara, Wialinsudd at FarOsund and also Faro, Lutterhorn and Stor 

 Myr in Rute. The Mineralogical Cabinet of the University of Upsala has a specimen 

 collected by Professor P. T. Cleve in the limestone of Slite. 



There exists a great variability in this shell, especially as to the width of the 

 umbilicus and the height of the spire as remarkable through the figures of the typical 

 specimen of Waiilknp.erg, which has been kindly lent from the Mineralogical Cabinet 

 of Upsala, with its low spire and flattened whorls to these globose shells delineated in 

 the fio;s. 26 and 27. Through the former, fig. 20 — 22, there can be no doubt of what 

 Waiilenberg really meant by his species. But there is no reason with him and Hi- 

 siNGEU to suppose that it also has been found in the Lower Silurian. I have not 

 seen a single specimen from that formation appertaining to this species. In Hisinger's 

 own collection there are specimens from Holmestrand in Norway, badly preserved, and 

 by him called Euomph. aaquilaterus. One specimen, the best, may possibly belong to 

 this species. In the same collection there are also specimens from Gotland called 

 Fiiomph. a^quilatcrns. They are five, much worn specimens of Oriostoma discors from 

 Kapellshamn and one specimen of Pleurotomaria undulans. Eiciiwald, Leth. Rossiea I, 

 II, 1170, adopts also this species, but the identification is questionable, as well as that 

 of Kjerulf in Veiviser p. 24. 



Sociotatis Ros;iac Seieiitianiin» was indeed printed already in 1818, as Waiilenbeiig himself says in the 

 beginning of the uAdditamenta" to that ni('nioir, page 293 of the same volume. The statement there 

 given is: »Post([nam anno 1818 imjiressa fuerat Conimentalio do r(^trilieatis Sveenni.i» eto. The me- 

 moir had also been early enough distributed by its author to some geologists, as ean be pereeived by 

 what PittONnNiART says in his "fhnslaees fossilesn (1S22) p. '<?, viz.".. M. Wahi.knbhro, dont le tra- 

 vail . . . n'est Venn a ma eonnaissanee fpi'en 1819". Hut on the title page of volume VIII, eonlaining 

 the eollectcd nicmnirs and papers, the year 1821 is printed, as it was not issued complete before 

 that year. 



