MUSEUM REPORT. CXXV 
Gasteropoda........ Lamarck. 
Picropadmicys: 0s. 4): ..  Deshayes. 
Hleteropoda ..... 65. Lamarck. 
Cephalopoda........ D’Orbigny. 
Pmrnem Wadhs (d:de6 ei ecsiewr Agassiz. 
Ce a eee Owen 
en ays) ay lids Mca ays Giebel. 
tammalia os0b es) de Giebel. 
The Committee recommend that this list, when revised and amended 
by the Council, may be transcribed, framed, and hung up in the Mu- 
seum, and that no departure from the principle or plan of arrange- 
ment so laid down shall be permitted to be made without a written 
order of Council. Changes of this kind involve consequences so im- 
portant that they should never take place at the mere fiat of an indi- 
vidual, or even of a committee. 
The professed object of the British Collection is to exhibit the 
various species of organic life in the order of superposition, not of 
juxtaposition—those that are seen on the vertical plane, not on the 
horizontal. Yet in carrying out this object the practice has been to 
give the right of entrée not merely to an individual of any given spe- 
cies, or to different varieties of such species, but also to other indi- 
viduals which agree exactly with that previously admitted, provided 
they are natives of a different district. Your Committee think that 
such repetitions should be allowed only when some peculiar geological 
interest is attached to the recurrence of the same fossil in two distinct 
localities in the same formation. 
Naming of Specimens. 
The naming of specimens of natural history is a very delicate, and 
at the same time a very laborious occupation,—one which can safely 
be entrusted only to few. It requires not only great experience, great 
erudition, great knowledge of the subject, an acquaintance with the sci- 
entific literature of Europe, but in addition to all these a kind of Euro- 
pean reputation. The curators who have had for some years past the 
direction of the Museum of the Society have all been men of that 
stamp ; but they, like their fellow-men, cannot be expected to arrive 
always at one and the same conclusion. Generic and specific names 
must necessarily change from time to time, as science advances, but 
all such changes should be rare, well-considered, and officially sanc- 
tioned. No curator can be expected to do his work well unless he 
has some guarantee for its durability. The generic and specific names 
which now attach to the specimens of the British Collection, as far 
as they are named, constitute, and ought to constitute, a very large 
part of its value; they are the result of an expenditure which cannot 
have amouuated to less than £4000, not to take into account the un- 
bought labcur and experience which at different times have been so 
generously volunteered on their establishment or rectification : these 
names the Committee hepe are, with few exceptions, correct ; but 
they are not yet recorded in any official document ;—the parties who 
