72 G. LINDSTItOM, (1N TtlR SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND. 



Gen. BELLEROPHON Montfort. 



Syn. 17S1 Naiitilites Hupscn p. p. N;iturs;eschiclite ties Niederdeutsclil. I, 23, pi. Ill f. 20 — 23. 

 1808 Bcllerophon Montfort Concliyl. Systematique, I, 50, 51. 

 1812 Ellipsolitlies Soweruy p. p. (iion Montf.) Miii. Conch, vol. 1, 81. 

 1825 Delhrophus Rlainville ("mala emendatio» Heumansen) Man. do C'oncliyliologie, 4. 

 1847 Ducauia Hall p. p. Pal. N. Y. vol. 1, 32. 

 1847 Carinaropsis Hall p. p. Tal. N. Y. vol. 1, 183. 



1849 Vasulites Hermansen (non Montf.) Ind. Gen. Maiac. Primordia II, 077. Sec; below. 

 1861 Phrai/viostomn Hall 14 Hep. N. Y. State Cab., 94. 



1882 iVaagchia De Koninck Notice sur la famille des P>elleroplioutid;v, Ann. Soc. Geol. de Pelgiqne IX, 14. 



This name being already given away by Neumayr it was changed by De Koninck into the fol- 

 lowing. 



1883 Waagenella De Koninck Fauna Carbonif. Pelg. II pt. IV. Explic. des planches, pi. 38. 



Shell globose, involute, ivitli the whorls in the same plan or nearly so, concave on 

 the umbilical side as niell as on the apical one, so that no distinction can be made between 

 them. Aj)ert'ure circidar or oval, suddenly m,uch. enlarged, lips thin, continuous, interior or 

 coltiinellar lip covering the back of the second convolution. The slit band is always distinct, 

 originating from a deep notch in the middle of the exterior lip; it is in several species 

 much varying, being elevated as a, keel on the last convoltition, sunk as a channel or aflat 

 band loiver down on the older whorls. It is covered, with quite the same sort of semihi- 

 nar, backwards curved umvelets as are seen in all Pleurotomarice. The umbilicus is in 

 the small specimens very large and opien and is in the older ones covered and hidden be- 

 neatJi the refl.exed margin of the aperture. In some, hoicever, it continues uncovered or 

 open. The exterior ornamentation of the shell consists of transverse strice, which often are 

 crossed by longitudinal ones. Moreover there is a. peculiar feature, observed in Gotland 

 specimens, consisting in a, series of thin lamina;, ivhich are nothing but the continuation of 

 the lines of growtli. They are gently curved, outwards and are most crouxled and per- 

 fect in the undnlical tube, ichere they have also been best j)rotected against fracture. These 

 lamina; may as in Tremanotus, each in its turn, have formed the successive ap>ertures and 

 tJien been partly absorbed, partly abraded and only jireserved, lohere they were protected. 



In explanation of the synonyms given above tiie following remarks may serve, 

 Ell/psolithes Sow. in Mineral Conchology, vol. I pp. 81, 83, 84 is not to be oonfonnded 

 with Montfouts genus of the same name which only contains Polythalamia. That of 

 SowERHY consists of one species of Nautilus, one, of Goniatites, and one of Bellerophon 

 (B. ovatus) according to his own emendation in Min. Conch, vol. 5 p. 107. But Mor- 

 ris, Cat. Brit. Foss. p. 302, regards them all as C<!phalopods. Bucania Hall Pal. 

 N. York vol. 1 p. 32 is chiefly distinguished thereby that the aperture is dorsally 

 abruptly expanded and that the volutions are all visible in the umbilicus. In the 

 fourth volume of Pal. N. York Hall seems to have abandoned his opinion on the di- 

 stinction of this genus and includes it amongst the Bcdlcrophons. The wide aperture 

 is moreover common with most of the Bellerophons and as to the uncovered and 

 large umbilicus Deshayes remarks in the -lournal de Concbyliologie vol. I p. 20r) 

 "I'existence de I'oinbilic est un caractere indift'erent», and not of importance enough to 



