186 BULLETIN OF THE 
beginning near the shores and extending to the abysses, while most 
deep-sea dredging parties have ceased work as soon as they came into 
comparatively shallow water, for fear of confounding what were sup- 
posed to be two sharply differentiated faune. We learn from the work 
of the “ Blake” that the differentiation is much less marked than would 
be anticipated, and that, in addition to the species found widely dis- 
tributed over the floor of ocean, there is an important contingent of 
species which are probably derived from the adjacent litorale, as well 
as a tolerable number which are found in water of all depths, from a few 
fathoms on the Florida coast to two thousand fathoms in the adjacent 
deeps, without affecting their external characters. Further exploration 
in other seas will probably prove that there are local faune in the ar- 
chibenthal areas, as there are on the shores, a conclusion which would 
accord well with what we learn from paleontology. 
One point has been brought out by the study of the Blake collections 
which was foreshadowed by Pourtaleés in his study of the deep-sea corals 
dredged by him in the vicinity of the Florida reefs. It is being con- 
firmed by present study of the mollusk fauna of our southern coast in 
connection with the tertiary and quaternary fossils of the Atlantic and 
Gulf slopes. It is that a large proportion of the tertiary shells which 
have been called Pliocene, or even Miocene, in this country and in 
Sicily, still exist in a living condition near our shores. The tertiaries of 
Calabria and of localities in the South of Italy having been pretty fully 
studied, Pourtalés was able to identify many of his corals with those 
found by Italian paleontologists. Had our own tertiaries been half as 
well known, or had he had a good collection of the shells of the southern 
and West Indian tertiaries, he would have been able to recognize their 
relations with his dredgings as being equally close. At least this is the 
case with the molluscan fauna, if not with other invertebrate groups. 
His dredgings, it should be clearly understood, were in the archibenthal, 
and not the abyssal region, which last his operations never reached, 
There is not enough known, so far, of the strictly abyssal mollusk 
fauna, to afford a safe basis for generalization in connection with these 
tertiaries. I may observe, however, that from middle Louisiana, on 
the edge of the Eocene beds, I have recently received certain fossils 
which present every appearance of being a deep-water (archibenthal ?) 
deposit, including ZLimopsis and several other characteristic forms. ‘The 
data which have been received relating to the circumstances under 
which the fossils are found are as yet insufficient for a satisfactory 
discussion of the subject. 
