690 ZOOLOGY. 
by the knowledge possessed at the present time ; that the topography 
and geology of that portion of the west American coast, specified 
by him, was much more uniform in its character, as well as in the 
temperature of its waters, than that of a corresponding section in 
extent of the Atlantic coast, to say nothing of the influence of the 
coast currents which upon our coast are peculiar, and which enter 
largely in the matter of distribution of species ; furthermore that 
the manuscript data in his possession, which were, to say the 
least, fully as important as what had already been published, and 
quite likely more authentic, indicated a greater range of coast to 
each province and therefore a less number of provinces than sug- 
gested by Prof. Verrill. ; 
Though much had been done by himself, and other members of 
the Academy cooperating with him, in the accumulation of data 
bearing upon the geographical distribution of the mollusca of our 
coast, still so much remained to be done in order to make the 
work thorough and reliable, that it would be merely arbitrary and 
necessarily require frequent readjustment to propose at this time 
any new divisions or subdivisions of the coast into zoological 
provinces. 
As to that part of the west coast of North America from Cape 
St. Lucas, including the Gulf of California, thence southerly to à 
point a few miles south of Panama, with the exception of collec- 
tions made at a few places in the Gulf of California, also at San 
Juan del Sur and its immediate vicinity on the coast of Nicaragua, 
and in the Bay of Panama, almost nothing more is known of this 
vast reach of shore line than was known years ago. 
Mr. Stearns stated that at some future time, as soon aS © 
collected’ by himself and colaborers here could be compiled, 
proposed to refer to this subject again. 
the data 
he 
SouTa 
On ZOOLOGICAL BARRIERS, WITH SPECIAL REFERENCE TO $ # 
hains and bro 
America.— How far the present lofty mountain-c ties 
rivers arrest dispersion is an interesting and important eee is 
Every fact throwing light upon it is a valuable contribu $ od 
science. It would seem that in temperate regions the mou 
are greater barriers than in the tropics. Mr. Darwin says *™ 
er p the organic be 
ings on the opposite sides of the Andes than on oppo! corrobó- 
the ocean. My own observations on the equatorial Andes 
AEE NEES SEN ae AE LEE AE AE E g EE cote S| A A 
; 
a 
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4 
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