KONGL. SV. VET. AKADEMIENS HAXDL. BAND. 19. X:0 6. . 29 



1. Ti'ijblidium reticulntum Ldm. 



2. Tryblidiiim unguis Ldm. 



3. Flati/ceras cornutum His. 



4. Pleurotoinaria limnfa n. n. 



5. PUurot. eliiptica His. 

 o. Pleurot. bicincta Hall. 



7. Pleurot. labrosa H.^LL. 



8. Pleurot. qualteriata Schloth. 



9. Euomphalus Gotlandicus n. 



10. Oriostoma rugosum Sow. 



11. Hubulites ventricosus Hall. 



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

 that island very little is at present known. As common with the nearest strata of Osel 

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

 ceras cornutum His. very common, Pletirotomaria ellijHica His., Pleurot. bicincta Hall, 

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

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



From the Upper Silurian strata of Scania at Bjersjolagard 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: 



Conularia Icevis n., Pleurotomaria eliiptica 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, PI. alata His., PL Lloydii Sow., PL bicincta Hall, Bellerophon trilobatus 

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

 Sow., Cyclonema carinatum Sow. 



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

 recorded as common. I have had access to a collection of 65 species of Bohemian 

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

 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 wEinige 

 Bemerkungen fiber die Podolisch-Galizische Siiurformation» (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. eliiptica His., Tryblidium unguis Ldm. occur 

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

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



