4 
Reviews—Dr. W. H. Dall’s Tertiary Fauna of Florida. 475 
material is available, yet it seems to us to be quite as convenient to 
give a “‘ specific” name to the extreme types of variation as to further 
burden the forms by adding a varietal cognomen—no one, in the 
present state of our knowledge as to the value of a molluscan 
“species,” is likely to be deceived thereby. The case at present 
stands thus:—If you have, say, four shells which can be readily 
distinguished from one another and exhibit a certain amount of 
striking difference, they would be called four “species,” without 
hesitation; if, however, “‘ enough material” be subsequently obtained 
and forms are found linking these four together, they would be 
regarded as one species only, but by way of compensation for the 
degradation thus sustained they would, perhaps, receive varietal 
names. 
We are not going to defend the “nouvelle école” to which Dr. 
Dall applies some well-merited strictures, on account of its “hair 
splitting” propensities; but it may be pointed out that if fig. 4 of 
plate xvi. of the work under review is to be regarded as the same 
species as that depicted on the same plate, fig. 1, viz. Turritella 
subannulata, then fig. 4 (var. acropora, Dall) and the whole of the 
forms included thereunder ought to be rigorously compared with 
T. acutangula, Broce. (syn. T. subangulata, Broce.), of the Southern 
European Miocene and Pliocene. The gaps existing between the 
American and the Huropean species alluded to are very slight, and 
could easily be bridged over. We possess specimens of both species, 
and some of the latter which we have from the Miocene of Pontlevoy 
(near Tours) are practically identical with the var. acropora. It 
would not be difficult to multiply examples of this kind, but we 
content ourselves with the foregoing for the present. 
This seems a fitting opportunity to remark on the ornate appear- 
ance of many of the North American Tertiary Turritelle; we have 
observed that wherever this genus is very abundant in the fossil 
state in Hurope it is usually more ornate than where it is sparsely 
represented, especially as far as the Pliocene is concerned. But we 
have nothing on this side to compare with Heilprin’s 7. perattenuata 
from the Floridian Pliocene; amongst other things it attains a 
length of 135-0 mm. with a maximum diameter at base of 13:5 mm. 
and exhibits no Jess than 44 whorls! Specimens of T. apicalis, 
Heilp., in our possession have 23 and 24 whorls respectively. 
The genus Solarium comes in for a good share of attention. 
Dr. Dall remarks that it occurs abundantly in the American Eocene, 
but has been generally misunderstood, the small Trochoid pearly 
shells properly called Solariella having in the United States, as in 
Europe, been frequently described under the name of Solarium, 
which latter is never pearly, and belongs to a wholly diverse line 
of development. The examination of the fossil species has led our 
author to subdivide the genus into sections. He remarks that the 
form of the shell in most of the groups may vary by having— 
(1) the whorls rounded at the periphery; or (2) the periphery 
keeled; or (8) with a shallow, wide sulcus on the top or base of 
the whorl near the periphery ; or (4) by having the spiral sculpture 
