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on the edges ; the mouth oval, undulated, and horizontal ; 

 the top pointed, and the siphon central." Fragments only 

 are found, some of which are three inches in diameter at 

 their base ; but the characters of the whole fossil do not 

 appear to be sufficiently known to warrant the founding on 

 them a new genus. It appears, undoubtedly, to have been 

 a multilocular shell of a considerable size ; but, previously 

 to removing it from the genus orthoceratites, and forming of 

 it a genus by itself, it is certainly necessary that more of its 

 generic characters should be determined. 



Molossus is a genus formed for the reception of a fossil, 

 which is named, by Professor Blumenbach, orthoceratites 

 gracilis, and is described as " A free, chambered univalve ; 

 straight, conical, tubular, and intersected ; chambers plain, 

 in form of a drum ; siphon lateral, continuous, round, and 

 serving for a mouth ; the top pointed ; the base horizontal." 

 Blumenbach describes the joints as being pyritical, which 

 leads, with the account of the chambers being intersected, 

 and the necessity of pointing out the continuity of the septa, 

 to believe there might be an agreement between these 

 bodies and the pyrites found at Dorking, which are cylin- 

 drical, pyritical bodies, with slender points passing out at 

 each end, much resembling those figured by M. de Montfort. 



Echidnis is a similar fossil with that which is figured 

 as a species of orthoceratites , (Organic Remains, vol. iii. 

 PL vii. fig. 14), its specific character being the alternate 

 circular risings and depressions on its surface ; but certainly 

 no characters have yet been shown which mark it to be of a 

 distinct genus. 



Achelois. The fossil, figured by De Montfort, as the 

 type of this genus, as being of a conical form, with conical 

 septa, and for which reference is also made to Knorr, Tom. ii. 

 sect. 1, PI. ii. A. viii. and Supp. Tab. iv. fig. 1, is very un- 

 satisfactorily described; nor is this description aided by 



