SCIENTIFIC RESULTS OF EXPLORATIONS BY THE U. S. FISH 

 COMMISSION STEAMER ALBATROSS. 



[Pulilishcd l)y iiorniission nf Hon. Mahsiiall McDonald, (,'oninii.ssionpr oC FisliRries.] 



No. XXV,— REPORT ON THE ,MOLLIISK-FAUNA OF THE GALAPAGOS 

 ISLANDS WITH DESCRIPTIONS OF NEW SPECIES. 



BY 



RoHKRT E. C. Stearn.s, Ph. D., 



Adjunct Curator of the Depai-tment of Mollusks. 

 (Witli Platen r,r, i.ii.) 



The following list of the land and marine shells of the Galapagos 

 Islands is based piincii)ally ou the collection made by Prof. Leslie A. 

 Lee and his. assistants on the voyage of the U. S. Fish CommiSvSion 

 Steamer Albatross from Chesapeake Bay by the way of the Straits of 

 Magellan to San Francisco in lS87-'88, Without any attempt to make 

 an exhaustive review of the mollusk-fauna of the group, or even to make 

 a list that would be a complete compilation or catalogue, I have in- 

 cluded the principal collections from authentic sources heretofore made 

 known or published, and have added such comments and notes as have 

 occurred to me in the course of my examination of the Galapagos ma- 

 terial collected by the Albatross and such other examples as are con- 

 tained in the collection of the U. S. National Museum. It should be 

 borne in mind that this report refers, so far as the marine mollusks are 

 concerned, with a few exceptions, to the littoral and shallow-water spe- 

 cies only. The deep sea material remains to be investigated and reported 

 upon hereafter by Dr. Ball ; the few species he has already described 

 are included in the summarized list in the latter ^art of this report. 



GEOGRAPHICAL AND PHYSICAL CHARACTERISTICS. 



A brief description of the geographical situation and physical char- 

 acteristics of the islands of this grouj) may be of some interest in con- 

 nection with what follows. The Galapagos are a group of islands in 

 the Pacific ocean, about (500 miles to the westward of the coast of Ecu- 

 ador, to which State they belong. They lie on both sides of the equator, 

 extending from about 2° north to 1° 30" south latitude, and between 

 89° 20" and 92° 10" west longitude from Greenwich. 



There are five principal islands, eleven smaller ones, and a great 

 number of islets and rocks. The larger islands, situated between the 



Proceedings National Museum, Vol. XVI. — No. 942. 



353 

 Proc. N. M. 93 23 



