PTEROPODA. 



The fossil remains of the Upper Silurian Pteropoda of Gotland are by no means 

 so common nor so characteristic of several beds, as arc those of the Gastropoda. As 

 I do not consider the Tentaculites as Pteropods in consequence of their close affinity 

 to the fixed Cornulitlies and similar, there is only one genus known. 



Gen. CONULARIA Miller. 



1818 Miller in Sowkkby's Mineral Concliology III. p. 108. 



Shell fyraiiiidal, o-xtremehj thin, of several strata, each of these homogenous and 

 transparent, brown or red; near the initial apex the shell is partitioned off by a transverse 

 diaphragina. Ajyex often deciduous. Aperture narrow, partially closed by tongiidike prolon- 

 gations from the corners. Side corners grooved or blunt. Along the middle of each face 

 there runs from the aperture to the apex one or in some species two folds, wliich project 

 only a little distance inwardly. In others they are totally ivanting or represented by one or 

 two longitudinal septa placed on the inner .side. Surface ornamented by transverse ridges, 

 smooth or tuberculated, forming an obtuse angle along the median line of the surface with 

 its apex directed towards the aperture. 



The systematic place of this genus and its allies has long been subject to some 

 discussion and difference of opinion. Among the various opinions on the nature of 

 Conularia may be armotated that it was ranged with the Cephalopoda by J. Sowerby, 

 Bronn, F. a. Roemer, Blainville, G. B. Sowerby, Fleming, Hoeningiiaus; this may 

 partly have been occasioned by a false appearance of a siphuncle in the diaphragm, 

 of which Hall still speaks as present in his Conularia trentonensis. D'Archiac and 

 Verneuil seem to have been the first who considered Conularia as a Pteropod and they 

 were in this view followed by D'Orbigny, Morris, De Koninck, Leonhard, G. Sandberger, 

 Austin and almost all later naturalists. 



H^ckel again, in his Morphologic vol. II, page cxiii, denies that the Conularia^ as 

 well as the other pala!ozoic fossils hitherto presumed to be Pteropods belong to that group 

 of Mollusca and he thinks that no true Ptero|)ods are found in a fossil state anterior to 



