16 AXEL A. OLSSON 



In more recent years, much additional collecting of Panamic mollusks 

 has been made under both professional and private auspices. In the former 

 class belong the extensive explorations carried out throughout the eastern 

 Pacific by expeditions sponsored by the New York Zoological Society under 

 the direction of William Beebe and that of the Templeton Crocker Expedi- 

 tion, the combined moUuscan material worked up by L. G. Hertlein and 

 A. M. Strong of the California Academy of Sciences and pubHshed in 

 various issues of Zoologica and in the Bulletin of the American Museum 

 of Natural History. In these papers, the authors have described a large 

 number of new species and extended the range of many others. Their 

 revision of Panamic Pelecypoda is especially important. 



The hobby of shell collecting and study amongst the Panama Canal 

 Zone personnel has expanded greatly since the war, and the author is 

 extremely indebted to many of the local naturalists who have contributed 

 specimens, extended their hospitality, or guided him on many a trip to the 

 beach. James Zetek, former resident manager of Barro Colorado Wildlife 

 Refuge, has been an ardent collector of both land and marine mollusks for 

 many years, and science is indebted to him for the discovery of many fine 

 species described by Dall, Pilsbry, and others. Walter D. Clark, a former 

 postmaster in the Canal Zone, ranks also as a good collector and through his 

 discoveries contributed many new species described in the main by Maxwell 

 Smith. Captain W. S. Bitler, USN, formerly stationed in the Zone, carried 

 on extensive dredgings in the vicinity of Panama City and around the 

 Pearl Islands and to whom the author is indebted for many specimens of 

 Oliva and Olivella containing the soft parts for radular extraction. 



3. COASTAL FEATURES BETWEEN PANAMA AND THE 

 NORTHWESTERN PART OF PERU 



Panama is naturally the center of the faunal province bearing its name 

 as well as by its historical associations. The extraordinary abundance of 

 marine mollusks at certain places in the vicinity of Panama City was 

 emphasized through the writings of C. B. Adams, and it has often been 

 debated whether shell life is still as abundant there as formerly. There is 

 little doubt that the construction of the canal resulted in great destruction 

 of marine life through its disturbances of the sea bottom, pollution, and 

 other factors, at least locally, but perhaps in some measure mitigated 

 through the creation of other environmental sites favorable to marine 

 growth such as the building of the Amador causeway of rock ballast, amongst 

 which many species live and breed. The entrance to the canal requires 

 almost constant dredging of the ship channel and much mud from this 

 source drifted on the tide has silted in considerable parts of the bay 

 opposite Old Panama, covering its bottom with a layer of black mud 

 leaving only a narrow beach at the upper tide level which can be safely 

 traversed on foot. Beach collecting at Old Panama is usually good and 

 such fragile species as Ha/rvella elegans, Pandora panamensis, and Nucidan-a 



