10 AXEL A. OLSSON 



in latitudes so near the equator, quickly sensed its cause, attributed it to 

 the cooling effects of a stream of cold waters swept northward along the 

 Peruvian coast by an oceanic current. As far as known, Humboldt's descrip- 

 tion and accurate diagnoses of the Peruvian current (now sometimes called 

 the Humboldt Current) is the first mention of this important oceanic 

 stream in the literature. Humboldt secured a few shells along the Peruvian 

 coast, others in Mexico, which were described by Valenciennes a few years 

 later. 



Humboldt's achievements in South America attracted widespread 

 attention in Europe and several other expeditions were shortly organized. 

 The first of these expeditions to South America was one sponsored by the 

 Museum National d'Histoire Naturelle de Paris who selected Alcide 

 d'Orbigny to serve as a travelling naturalist and to explore the southern half 

 of the continent thus complementing in some respects the work accomplished 

 by Humboldt in the north. D'Orbigny at the age of 24, was excep- 

 tionally well qualified for this task, both in the fields of zoology and in 

 geology. He sailed from France, the 31st of July, 1826, and about a month 

 later, landed at Rio de Janeiro at a time of war between Brazil and Argentina. 

 Over the next six years, D'Orbigny travelled through a large part of south- 

 ern Brazil to Argentina, then into Bolivia, Chile, and finally to Peru, often 

 through wild, unexplored, and at times dangerous country. He finally 

 reached Lima and while there met M. Fontaine, a countryman of his and 

 a physician on the French warship, the Griffon then anchored in the road- 

 stead of Calloa. The two close friends roamed the countryside and dredged 

 for mollusks in the harbour. After a stay of about 10 days, D'Orbigny 

 departed for France while Fontaine continued his collecting of both shells 

 and fossils as far north as Paita. 



The work of D'Orbigny on the natural history of South America is 

 monumental in its scope, the results published in five magnificently il- 

 lustrated volumes ("Voyage dans I'Amerique Meridionale") issued from 

 1835 to 1847. The volume on the mollusks is a work of 758 pages (quarto) 

 and illustrated by an atlas of 85 (82 colored) plates many of the figures 

 showing the extended animal. This is the largest single work devoted ex- 

 clusively to South American Mollusca, but as far as the marines are 

 concerned, it deals mainly with southern species from Peru, Chile, and the 

 Argentine. 



The visit of Charles Darwin to South America as naturalist and 

 geologist aboard HMS Beagle commanded by Captain Fitz Roy followed 

 that of D'Orbigny or with a small overlap. The two naturalists did not 

 meet in the field. Although Darwin's work led to important results in the 

 fields of geology and paleontology and in laying the foundation for his 

 later studies in evolution, Darwin paid no particular attention to Recent 

 mollusks, his chief interest in shells was their occurrence in high level 

 terraces and as indicators of uplift along certain parts of the coast of Chile 

 and Peru in relatively Recent times. 



