474 Reviews—Dr. W. H. Dall’s Tertiary Fauna of Florida. 
pre-occupation), and Locochlis, D. and M., are very properly 
regarded as distinct from that genus. 
Some very suggestive observations are made under Cerithium, 
which deserve to be made more widely known. The author remarks, 
and we think pertinently, that the sub-divisions into which the 
genus has been split up are worthy of more extended comparative 
study than they have hitherto received, but unfortunately does 
not attempt to enter much into detail in regard to the matter, 
for reasons that are sufficiently obvious, in a special work of the 
kind under review. He states, however, that in sorting over large 
numbers of specimens of one species, either recent or fossil, it will 
be noticed that there are two sets as it were, otherwise similar, one 
much more slender than the other. We can quite bear out this 
observation in regard to many European Tertiary fossils belonging 
to the group. This, he says, may be a sexual difference; it is 
observable in Bittium and Seila also. “The principal variations of 
the species are; Ist, size, there being in almost any large lot a few 
or possibly many dwarfs, otherwise similar—recalling the difference 
of size in Cyprea; 2nd, in the intensification of (a) the transverse, 
wavy sculpture, which, in any species which has it, may be strong, 
weak, or wholly absent; (6b) the nodulations or tessellations of the 
primary spiral bands or revolving ridges, which vary in the same 
species from obsolete to very sharp and prominent; (c) the pro- 
minence of the primary bands, which is very variable, apart from 
the nodules they may bear. The secondary fine striation, as in 
Buccinum, is much more constant in its features than the coarser 
sculpture.” 
The only reservation we would make to this is, that unless in 
possession of very ample materials the paleeontologist would have 
some difficulty in determining how far the variations recorded might 
be regarded as of specific value; whilst it is certain that what might 
be called a mere deviation from the type in some very variable 
species would in others, usually more stable, be looked upon as 
characters having a higher importance. It has been remarked that 
the scarcity of Cerites is characteristic of the American Tertiary, but 
our author thinks that this is due rather to ignorance of the fauna 
than to anything else, and he makes substantial additions in the 
present paper to the number of species of Cerithium hitherto known 
to occur in the United States. 
The author has given considerable attention to Turritella, which 
in some respects is a most unsatisfactory genus to deal with. In 
speaking of T. subannulata, Heilp., he refers at some length to the 
variation which that species exhibits, and states that some people 
would find fifty or sixty “species” amongst the material in which 
he can only see one. There is much wholesome criticism in the 
general tendency of this remark, but at the same time we should be 
careful to make it apply all round. Given “enough material” it 
should be possible to trace gradations from most of the “‘ species” 
of a genus, through space and in time, to one another. We quite 
sympathize with the author in his difficulties where a mass of 
