BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND. 7. N:0 5. 25 



In tlie subjoined list of tlie forms lierein described and 

 figured, I have indicated by marks in the different cokimns, 

 those forms which also occur in the Wenlock and Ludlow 

 series of the AVest of England and in the Cincinnati, Clinton 

 and Devonian strata of Canada. From this list it will be 

 seen that of the 4l different forms from Gotland, there are 

 15 which also occur either in England or Canada. In the 

 English Wenlock are 9 forms and in the Ludlow 2, which 

 are common to Gotland. In the Cincinnati series of Canada, 

 there are 6 forms which occur in Gotland, and two of these 

 are also common to the English Wenlock. In the Clinton 

 series of Canada are found 4 of the Gotland forms, whilst 

 a single form is common to the Devonian of Canada. As a 

 rule it may be stated that the jaws which are also present in 

 England and Canada, are, with one or two exceptions, the 

 uiost abundant forms in Gotland, whilst those which are limi- 

 ted to Gotland are of rare occurrence. From the examples 

 figured, some idea may be formed of the abundance and 

 variety of the errant annelids in the Silurian seas, particularly 

 when it is remembered that these jaws have all been obtained 

 from the surface of a few square metres of rock at Fröjel 

 and from about a kilograrame of decomposed shale from Wisby. 



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