KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:0 6. 73 



be of value as generic distinction. Equally unimportant is the character added by De 

 KoNiNCK and Waagen that the shell is provided with longif.udinal or spiral striai, which 

 cross the transverse ones. Carinaropsis Hall Pal. N. York vol. I p. 183 consists of Ga- 

 stropoda belonging to different genera. Carin, carinata in all probability is a Bellerophon 

 of the large, compressed species, while C. patelliformis and C. orbiculatus are evidently 

 Patellid shells. Phragmostoina Hall 14 Rept. N. York St. Cab. p. 94 is also likely to 

 be a broad, compressed Bellerophon. Waagenia De Koninck Ann. Soc. Géol. de Bel- 

 gique 1882 p. 14, is distinguished only by callosities around the umbilical region. 

 Hermannsen in his Index ^) has VasuUtes as a synonym of Bellerophon, but no siich 

 generic name is found in the book cited^) by him. Montfort in his Conchyliologie sy- 

 stématiqiie ') himself cites B. vasulites from Hist. Naturelle des Mollusques, though only 

 as a specific name. 



Various efforts have been made by some authors to arrange the species of Bel- 

 lerophon in different groups. De Koninck in his older work*) and Stache") both pro- 

 pose two series, one characterized by an elevated dorsal keel, the other by a sunk slit 

 band. But as it is evident, that generally in young specimens the slit band is sunk 

 and in older specimens of the same species becomes an elevated keel and when more- 

 over this change can be traced in the same specimen, this characteristic is not to be 

 raaintained. Nor is it possible to apply the differences, which lie in an open or clo- 

 sed umbilicus as this character is changing in one and the same specimen. It seems to 

 be of raore avail to group the different species, at least the Silurian ones, according to 

 the pattern of the ornamentation. Å good characteristic of several species is found in 

 the size of the angle, in -which the transverse striaa join the slit band, as well the man- 

 ner in which they continue towards the sides. There is in very small specimens, of 

 B. latevittatus especially, a peculiar feature in a strong transverse groove (étranglement) 

 on the nucleus near the expanded apertural börder. It reminds highly of what is seen 

 in the small individuals of the Goniatites. But as similar grooves or necks are seen 

 in other Gastropodä, as for inst. in Platyceras and Euomphalus, it needs not point to a 

 Cephalopodan affinity of the Bellerophons as some authors have thought. This trans- 

 verse sulcus is quite as deep in the middle of the shell as on the sides. 



As to the geological history of this genus in Sweden, it may be remarked that 

 the oldest specimens are already present in the Inferior Gray Orthoceratite limestone 

 at Kongs Norrby, froiri where three different species have been found, and in the Superior 

 Red Orthoceratite Limestone at Skarpåsen, both localities in Ostrogothia. Specimens 

 have also been collected in almost all Lower Silurian regions of Sweden as Öland and 

 Dalecarlia. I have not been able to identify with certainty a single species of the 

 Gotland Bellerophons with those from other Silurian strata, excepting B. trilobatus. 

 In the shale beds at Westergarn some few, badly preserved specimens have been found 



I) Vol. II p. 677. 



-) Denys-Montfort Hist. Nat. des Moll .... siiile a rilist. N. de Buffon et Soniiini. Vol. IV p. 298. 



■'') Vol. I p. 51. nelleroplioti vasulites. 



■*) Anim. foss. de licloique p. 338. 



ä) .labrbucli der Gcol. Reiclisanstalt 1877, M 3, p. 297. 



K. Sv. Vet. Akail. HanclI. Bd. 1!1. N:o Ii. 10 



