58 
tations been published ;* the Getius has, however, been 
uniformly admitted as distinct. Its great resemblance 
to Crenatula, has sometimes induced me to think that it 
ought to be joined with that' Genus ; but a close com- 
parison of the hinges in many specimens of different 
species, all of which are wholly destitute of the spoon- 
like processes characteristic of Crenatula, joined with a 
consideration of its prominent beaks and gibbose form, 
has confirmed my Father’s opinion, and proved the ac- 
curacy of his judgment. Brongniart not knowing which 
species was the type of this Genus, and thinking the very 
prominent, unequal beaks of the two species belonging 
to the second section, a sufficient reason to distinguish 
them from it, has placed it in a newly formed Genus, 
which he has called Catillus ; but he probably was not 
sufficiently acquainted with the hinges of the species he 
still retains as Inocerami, to perceive their resemblance 
to the type. As to the Genus Perna, its species are of 
a much more foliated structure, and have a considerable 
sinus for the passage of the byssus ; it is, therefore, 
readily distinguished. 
The name Inoceramus, from V* (fibra) and nepa/uos 
(testa) is justly objected to by scholars, as an improperly 
formed word, and not expressive of u fibrous shell” 
which it was intended to signify ; it therefore ought to 
be changed, but it has been in use so long, that it has 
become general ; and, if I were even inclined to act the 
part of an innovator, to do so would, I think, only be 
adding to the confusion already existing in consequence 
of Brongniart’s naming the type of the Genus, Catillus, 
a name not applicable to the whole of the species. 
This Genus occurs in many strata from the Mountain 
Limestone to the Chalk. 
*See Mr. Mantell’s observation upon the knowledge of the structure 
of this shell, page 212. and compare it with the paper in Linn. Trans. 
Vol. XIII. page 455, &c. 
