SMITHSONIAN EXPLORATIONS. I929 IO9 



salts supplied an abundance of AinpuUaria, Marisa. Plaiwrbls and 

 Pahidcstrina ; these specimens being present from the source of the 

 little stream to where it merged with the acid water of a larger stream 

 coming from the volcanic mountain side, a distance of about the 

 length of two city blocks, when they completely disappeared, being 

 unable to maintain themselves in such an unfavorable environment. 

 This alkaline water was doubtless also stocked by migrating waders 

 and birds carrying the eggs or young of these mollusks on their feet 

 probably from Trinidad, the nearest place where they occur. 



Septeml)er i to September 4 we spent on Trinidad, the largest and 

 most beautiful of all the Lesser Antilles, stop]:)ing now in the lowlands, 

 now on the summit of its high mountains exploring pools and streams 

 and even the puddles in the asphalt \)\i that is pavinj^- United States 

 streets. Thanks to the officials of the Imperial College of Agriculture 

 and their friends, particularly Professor F. W. Urich, every moment 

 of our time was used to the best advantage. Trinidad is such a large 

 island with such a diversity of habitats that a month of collecting 

 would be hardly enough to harvest its possibilities. It is to be hoped 

 that this will be done in the future by the students of the Imperial 

 College of Agriculture under the wise guidance of Professor Urich. 

 Here as elsewhere we found the forest fauna a scanty one. but where 

 limestone was present an abundance of species and specimens was 

 assured. 



Having completed the southward swing we headed for Margarita 

 Island off of the Venezuelan coast and spent September 7 and 8 

 collecting in this dry and bleak habitat, which, in spite of its unfavor- 

 al)le appearance, yielded a host of land mollusks and other things, 

 the next island, Orchilla, however, yielding not a single land shell. 



We therefore promptly set sail for El Roque, a collection of islands 

 and islets west of ( )rchilla. and devoted jiart of a day to a careful 

 search of its tall main island at the western end of the group. Here, as 

 on Orchilla, land mollusks were conspicuous by their absence, but the 

 place was swarming with lizards, and birds were equally abundant in 

 its mangrove swamps ; we added a goodly number of each to our 

 collections. 



To give even a half-way satisfactory description of the next islands 

 visited, Bonaire, Curagao, and Aruba, would require more space than 

 is available — suffice it to say that our visit to them yielded among other 

 land shells, a handsome lot of Ccrion, whose presence here is one of the 

 most fascinating problems of geographic distribution in the whole 

 field of mollusks, their nearest relatives being in Porto Rico. 



