M. Defrance on Bellerophon. 223 



animals are inclosed in or inclose these shells, but I must beg of 

 some of my friends who live on the sea side, to send me some in 

 spirits, for I doubt their being similar to those which form the 

 Nautilus Spirula, a kind of Cephalopode ; although my friend Mr. 

 J. Sowerby pointed out to me the affinity that exist between 

 these shells and the bone of the cuttle-fish; perhaps Montague may 

 not be very wrong in placing them with the Annelides. 



[To be continued,"] 



Art. XXV. Correction of the Characters of the Genus 

 Bellerophon, established by De Montfort, in his Conchy- 

 liologie. By M. Defrance.* 



Several species of fossil shells are found in the Eissel, a canton 

 of the duchy of Juiiers, in the environs of Chimay, a small town of 

 the Pays Bas, and in Ireland, which Denys Montfort, and other 

 authors have placed in the genus Bellerophon. This genus, is 

 classed, in the Conchyliologie systematique, with the chambered 

 univalve shells, and amongst other characters assigned to it by 

 the author, has smooth septa perforated by a siphon. 



Unfortunately, this naturalist, although possessed of remarkable 

 talents, has nevertheless committed very numerous errors, both in 

 his descriptions, and in the figures which he has published One 

 of these errors is the assertion that the shells of the genus Bellero- 

 phon are chambered. I possess two species of them, one of 

 which belonged to De Montfort's collection, and perhaps served 

 as the type for the description and figure which he has given at 

 page 51 of the work quoted above. Having suspected that these 

 shells, filled with calcareous spar, are monothalamous, I sawed 

 one of them through, transversely, and found, in fact, that it is 

 convolute, like the Nautilus, but that it has no septa ; so that 

 instead of belonging to the division of Polythalamous Cephalo- 



* Translated from the original, in the Annales des Sciences Nalurelles, 

 vol. i. p. 264. 



