no. 1704. A COLLECTION OF SHELLS FROM PERU—DALL. 191 
The notion that the mournful colors of so many of the species 
might be correlated with the huge beds of kelp characteristic of 
these shores seems to be negatived by the fact that.in California 
similar kelp beds afford a shelter to some of the most brightly colored 
Trochide, etc., and that, as | am informed by Mr. Coker, red and 
green seaweeds are abundant on the rocks below low-water mark, on 
a large part of the coast of Peru, and presumably also of Chile. 
This and a number of other problems await the investigations of the 
future. 
Lastly, a survey of the characteristic groups of which the fauna 
is largely made up leads to the conclusion that the fauna is chiefly 
of southern origin. In spite of the fact that many species are com- 
mon to the Panamic fauna and a relatively small number to the 
Magellanic fauna, the more conspicuous types, like the blackish 
species of Tegula, have a Magellanic rather than a tropical character. 
This particular group has extended its range to Alaska on the north 
and Japan on the northwest, but its metropolis is in southern Chile. 
The type represented by the various species of Thais and Acanthina 
has traveled the same road, and so has the Protothaca group of 
Veneride. 
If we may accept as the original metropolis of a special type of 
mollusks that region where it is developed in the greatest number 
and variety of species, and perhaps also with the most extreme 
limits of size and ornamentation, we shall have for example Buccunum 
and Chrysodomus focused in the boreal Pacific region, certain types 
of Thais and Acanthina in the region of southern Chile. 
Cook has called attention to the relation between Thais lapillus 
and the Oregonian T. lamellosa, and other species in the Tropics of 
the Panamic and Antillean region; but, viewed from an Eastern 
Pacific standpoint, the relatively few Atlantic forms may easily have 
originated in the Pacific, where their existing representatives show 
a much more luxuriant development. 
There is only one Thais of the Nucella type in the North Atlantic, 
but the North Pacific has five or six. It is very remarkable that in 
the Peruvian Province we have not a single distinctively old world 
type of mollusk. ‘Those which seem to be such are really cosmo- 
politan types, more familiar to us from old world localities, perhaps, 
but not necessarily of old world origin. 
