864 The American Naturalist. [October, 
NEW OBSERVATIONS ON THE ORIGIN OF THE 
GALAPAGOS ISLANDS, WITH REMARKS 
ON THE GEOLOGICAL AGE OF 
THE PACIFIC OCEAN. 
By G. Gave, PED., 
ASSOCIATE-PROFESSOR OF PALEONTOLOGY, UNIVERSITY OF CHICAGO. 
No. II. 
THE GEOGRAPHICAL DISTRIBUTION OF DIFFERENT ANIMALS IN 
THE PACIFIC AND INDO-PACIFIC OCEANS. 
We will now examine the distribution of a number of ani- 
mals in the Pacific, in order to find out how this distribution 
agrees with the theories of the origin of this Ocean. 
Ortmann” has shown that there is a uniform Indo-pacific 
Litoral Region. 
Distribution of Pocillopora Lam. 
Pocillopora,” a coral of the Madreporaria, is found only in 
the Indo-pacific region. It is represented by an extraordinary 
large number of forms reaching north to the Loo Choo and 
Sandwich Islands, and it is also common on the west coast of 
America. It is totally absent, however, from the Caribbean 
or West Indian Sea and the eastern American coral region. 
A few fossil forms are known since the miocene, Pocillopora 
madreporacea (Lam.), from Dax and Turin. 
It is of the highest interest, that the members of the Decapod 
Family Trapeziide” shows exactly the same distribution as 
Pocillopora. I am greatly obliged to my friend Dr. Ortmann 
for calling my attention to this fact. In his recent paper on 
28 Ortmann, Arnold E. Grundzüge der marinen Thiergeographie. Jena, 1896. 
* Ortmann, A. Studien über Systematik und geographische Verbreitung der 
Se Zoolog. Jahrb. Abtheil. f. System., II, Band, p. 143-188, Tafel 
* Ortmann, Arnold E. Die geographische Verbreitung der Decapoden Familie 
Trapeziide. Zool. Jahrb., Abth. f. System., X, Band, p. 201-216, 1897. 
