266 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
long ago pointed out, because it is the only place where the bottom is _ 
normally bathed by water varying only a few degrees, either way, from 
50°. Deeper down the slope the bottom water is constantly colder; — 
nearer the shore it is so for at least part of the year. Along this zone, 
too, salinity is much more constant than it is nearer the shore, as well 
as higher, and probably with but little seasonal change. Added to 
these hydrographic advantages, is the abundant food supply which 
usually characterizes the contact-zone between warm and cold waters, 
the importance of which was long ago realized by Verrill (1881). The 
result is that the bottom fauna of this zone is remarkably rich, both in 
species and in individuals, and largely of southern origin (Verrill, 1880, 
1881, 1884b). But its biological advantages are partly compensated 
for by its dangers, for at least once within the memory’ of man its _ 
inhabitants have suffered widespread destruction, the surface, for 
some hundred of miles, being strewn with the dead bodies of the tile- 
fish (Lopholatilus), as so graphically described by Collins (1884) and 
Verrill (1882, 1884b) and often commented upon by subsequent 
writers (Murray, 98, Murray and Hjort, 1912, Sumner, Osburn, and 
Cole, 1913). And at the same time the invertebrate bottom fauna 
was practically obliterated (Verrill, 1884a, p. 656; 1884b). Verrill 
believed that this was due to an off shore movement of the cold bottom 
water on the shelf, under the influence of violent northerly storms 
which swept the coast during the late winter and early spring of 1882. 
And whether this was the true cause, or whether an unusual accession 
of northern, or of abyssal, water was to blame for the lowered tempera- 
ture observed by Verrill in that year (p. 239), the occurrence serves to 
illustrate the fluctuations to be expected along the meeting zone of 
cold and warm waters. And it was evidently not a unique, though 
no doubt an unusual occurrence, for in July, 1884, the ALBATROSS 
encountered great numbers of dead cephalopods floating on the sur- 
face, over the 100 fathom curve, further south (Lat. 37° 47’, Tanner, 
1886). Conversely the failure of various northern littoral animals to 
extend their ranges beyond Cape Cod, is probably due to the excessive 
summer warming, partly due to solar heat, but also to sporadic flood- 
ing by Gulf Stream water. 
