GENERAL REMARKS. 
XHE second edition of the Historia Conchyliorum is a work which has been so long and 
universally referred to by every naturalist who has published on either recent or fossil shells, 
that any alteration in the numbering of its plates would lead to much confusion, and I have 
therefore adhered strictly to Dr. Huddesford’s arrangement. Several irregularities have how¬ 
ever crept into this arrangement; and by these Dr. Maton and Mr. Rackett have been led to 
suppose, that seven of the original plates are missing. Neither of the plates is marked either 
with 89, 164, 195, 196, 222, 923, or 961 : and, on the other hand, the number 101 has been 
given to three plates; and there are also duplicates of the following numbers, 168, 512 , 822 , 846 , 
883 , 931 , 965, and 990. Three of the seven missing plates have been obviously removed to 
the Tabulae Anatomicae; and if it can be satisfactorily shewn, that tab. 164 and 961 have been 
accidentally misplaced and wrongly numbered, we may fairly assume, that the remaining two 
are also to be found, either among the supernumerary plates, or in the anatomical department, 
although circumstances may not allow of their equally clear detection. 
For the omission of tab. 89 it is difficult to account; but it is plain, from the neighbouring 
irregularity of the numbers by which the figures are distinguished independently of the plates, 
that there has been some derangement of their original order; and as the materials for the 
two departments have been obviously intermixed, it may not improbably have been removed 
to the Tabulae Anatomicse. 
The plate which ought to have been numbered 164 is unquestionably misplaced, and is 
the supernumerary tab. 168 a. Tab. 165 is one valve of Ostrea Jacobcea; and tab. 166, which 
contains the other valve, is marked “ idem,” to denote its connection with the preceding 
plate: in like manner tab. 168 a. is marked “ idem,” with reference to tab. 163 ; for they con¬ 
tain the two valves of Ostrea maxima; and the former has no such affinity with tab. 168, 
which it follows in the present arrangement. 
Tab. 195 and 196 have been removed to, and now constitute numbers 15 and 16 of the 
Tabulae Anatomicse, as is plainly indicated by these original numbers, which have been suf¬ 
fered to remain in the corners of the plates. 
Tab. 222 is also proved in the same way to be number 18 of the Tabulae Anatomicae; but 
it should be brought back to its original place, for it simply contains a valve of Mytilus mar- 
garitiferus, and has nothing to do with anatomy. On the other hand, tab. 53, and the plates 
from 102 to 105 , should be removed to the anatomical department. 
For the omission of tab. 923 I am unable, with any degree of certainty, to account: but 
some plate may originally have been thus numbered, which it was afterwards thought would 
stand better in another section; or it may by accident have been wrongly marked, and placed 
elsewhere. The duplicate tab. 822 b. contains figures of Buccinum plumatum and Murex 
crassus; neither of which belongs to the section of volutes, where they now stand; and it may 
not improbably have been intended for this missing number. 
Of tab. 961 a much more satisfactory account may be given, for the supernumerary tab. 
931 is altogether misplaced; and I think there can be no doubt, that it has been accidentally 
marked with a 3 instead of a 6, and that it was intended to follow the Tritons at tab. 659 and 
660. It is worthy of remark, that the figure of tab. 168 a. which is so clearly proved to have 
been misplaced, is not distinguished either by any name or number; and the same omission 
occurs in tab. 931, and must have rendered both these plates much more liable to derange¬ 
ment, than if they had been marked in the usual way. 
Penllergare , January 12, 1823 . 
