KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 29 



1. 2'ryblidiiim retictdatum Ldm. 



2. Tryblidium ungids Ldm. 



3. Platyceras cornutum His. 



4. Pleurotomaria limat.a n. n. 



5. Pleurot. elliptica His. 



6. Pleurot. bicincta Hall. 



7. Pleurot. labrosa Hall. 



8. Pleurot. qualteriata Schloth. 



9. Euomphalus Gotlandicus n. 



10. Oriostoma rugosum Sow. 



11. Subulites ventricosus Hall. 



In regard to the distribution of the Gotland Gastropoda beyond the limits of 

 that island very little is at present known. As conimon with the nearest strata of Ösel 

 and Estland the following species have been annotated: Tryhlidium unguis Ldm, Platy- 

 ceras cornutum His. very common, Pleurotomaria elliptica His., Pleurot. bicincta Hall, 

 Oriostoma angulatum Wahl., Or. sculptum Sow., Or. cliscors Sow. very common, Pleurot. 

 planorhis His., Autodetus calyptratus Schrenk, Pleurot. qualteriata var. 



From the Upper Silurian strata of Scania at Bjersjölagård and Klinta I have 

 seen Platyceras cornutum His. Platyc. enorme Lindstr., Autodetus calyptratus Schrenk 

 and indeterminable nuclei of Murchisonia, Pleurotomaria and Bellerophon. 



From Norway, I have only seen the few following species: 



Comdaria Icevis n., Pleurotomaria elliptica His., Oriost. globosum Schloth. In com- 

 mon with England the following species have been found viz. Platyceras cornutum His., 

 Platyc. spiratum Sow., Pleurotomaria limata nom. nov. (= Euom. carinatus Sow.), Pl. 

 labrosa Hall, Pl. alata His., Pl. Lloydii Sow., Pl. bicincta Hall, Bellerophon trilobatus 

 Sow., Loxonema sinuosum Sow., Oriostoma cliscors Sow., Or. rugosum Sow., Or. sculptum 

 Sow., Cyclonema carinatum Sow. 



With the rich fauna of Boliemla not a single species can, for the present, be 

 recorded as common. I have had access to a collection of 6.5 species of Bohemian 

 Silurian Gastropoda, acquired by the State Museum of Sweden from the late M. Schary 

 of Prag, and I cannot find in it a single species to identify. Euomphalus pulcher 

 Barrande comes very near to Oriost. Roemeri and Euom. simplex Barr. near to Oriost. 

 sculptum Sow., but they are probably different. 



From the Silurian formation of Podolia and Galizia Friedr. Schmidt in »Einige 

 Bemerkungen iiber die Podolisch-Galizische Silurformation» (1875) p. 17 enumerates 

 six species of Gastropoda, but of these Euomph. (Pleurotomaria) alata is probably the 

 only one which can be considered as identical. 



Von Alth gave in 1874 a list of Silurian Gastropoda in his work »Ueber die 

 palseozoischen Gebilde Podoliens», page 31, amounting to 14 species, but as I have not 

 seen a single specimen of them, I can not with any certainty identify them with those 

 from Gotland. 



Of N. American Silurian Gastropoda I have found as identical, Platyceras cornu- 

 tum His., Pleurotomaria labrosa Hall, Pleurot. bicincta Hall, Subulites ventricosus Hall. 



Pleurotomaria bicincta Hall, Pleurot. elliptica His., Tryblidium unguis Ldm. occur 

 in the highest strata of the Lower Silurian of Estland and Pleurot. elliptica, Pleurot. 

 qualteriata are common with the Orthoceratite limestone of the Lower Silurian of 



