524 Correspondence—Dr. A. M. Davies. 
congeneric only with P. leptosoma as Gregory maintained, or only with 
P. biforis as I have hypothetically imagined, then the name Sturtzura 
stands. (Internat. Rules, 1905, Art. 29, ) 
That the rule referred to in the phrase ‘‘ once a synonym, always a 
synonym”’ has no bearing on either of these suppositions, is evident 
when its meaning is understood. The rule, in fact, simply states that 
a generic name once used in zoological nomenclature cannot be used 
for any subsequent genus that does not include the original genotype, 
even when the name as first used has proved to be a synonym. But 
if the rule does not forbid the resuscitation of Sturtzwra for a genus 
containing the genotype S. brisingoides, it certainly does forbid its 
use for a genus comprising only S. Jeptosoma and WS. leptosomordes. 
(Internat. Rules, 1905, Art. 36.) 
Mr. Chapman may not approve of these rules, and I do not pretend 
that I like them all myself. But in these matters of form it 1s surely 
better that individuals should come into line with the great majority 
of their colleagues. 
My protest against the composition of certain names was not made 
from the standpoint of a museum curator, as Mr. Chapman seems to 
suppose, but from that of the compilers of the Stricklandian code, who 
desired to render ‘‘ our scientific language palatable to the scholar and 
the man of taste.” If a name is held to have no meaning, let it at 
least be euphonious; but if itis intended to have a meaning, that need 
not be a ridiculous one. 
As for the more important matter—the homologies of the arm-ossicles, 
there seems no grave objection to the compromise now proposed by 
Mr. Chapman. But whether the ambulacrals consist of one piece as 
I suggested, or of two pieces as he now suggests, will probably not be 
decided until we find specimens with the stereom undissolved. 
F. A. Baruer. 
Lonpon, 7 October, 1907. 
COLLODION AS A PRESERVATIVE FOR FOSSILS. 
Srr,— Dr. Bather’s interesting article on collodion imprints reminds 
me of an intention I have long had of communicating to you another 
use for collodion. ‘The usual method of preserving fragile fossils by 
application of a hot gelatine solution is one which I have always 
found troublesome and unsatisfactory. Some years ago a student 
suggested to me that a solution of collodion would penetrate more 
readily, could be used at ordinary temperatures, and would become 
solid more slowly. He gave me some solution that he was using for 
some other purpose—a saturated solution of gun-cotton in equal parts 
of amyl acetate and ethyl alcohol. I found this answer very well, 
both for preventing the flaking of delicate fossils and for mending 
broken ones. Small specimens can be simply immersed in the 
solution, left there (in a corked tube) for an indefinite period, and 
finally lifted out and dried. Larger ones may be painted over, several 
times if necessary. I have by this means mended, among other 
things, broken specimens from Wenlock Limestone and Chalk Marl, 
