ALEUTIAN TROVINCE. 77 



Additional information on the fauna of this province has been 

 recently supplied by Mr. Lord, the natui-alist to the British 

 North American Boundary Commission Expedition, and by Dr. 

 Kennerley , the naturalist to the American North-west- Boundary 

 Exploring Expedition. The results obtained are discussed by 

 Dr. P. P. Carpenter.* 



Provinces on the Western Coast of America. 



The moUusca of the Western coast of America are equally 

 distinct from those of the Atlantic and those inhabiting the 

 central parts of the Pacific. 



Mr. Darwin states in his Journal (p. 391) that " not one single 

 sea-shell is known to be common to the Islands of the Pacific 

 and to the west coast of America," and he adds that " after the 

 comparison by Messrs. Cuming and Hinds of about 2000 shells 

 from the Eastern and "Western coasts of America, only one 

 single shell was found in common, namely the Purpura patula, 

 which inhabits the West Indies, the coast of Panama, and the Gal- 

 lapagos." Even this single identification has since been doubted. 

 Mr. Cuming, who resided many years at Valparaiso, did not 

 discover any West India specimens on that coast, and M. 

 D'Orbigny makes the same observation. On the other hand 

 M. Morch, of Copenhagen, says he has received Tellina opercu- 

 lata and Mactra alata from the west coast and also from Brazil ; 

 and M. Deshayes gives the following extraordinary ranges in 

 his " Catalogue of Veneridoe in the British Museum ": — 



Artemis angulosa, Pliilippines — Chili. 

 Cytherea umbonella, Ked Sf a — Brazil. 



„ maculata, W. Indies — Philippines, Sandwich. 



„ circinata, W. Indies — West coast America, 



In these instances there is doubtless some mistake, either 

 about the locality or the shell. As regards the last, Mr. Carrick 

 Moore has shown that the error has arisen from confounding 

 the Cytherea alternata of Broderip with C. circinata of Born. 

 M. D'Orbigny collected 628 species on the coast of S. America, 

 — 180 from the eastern side, and 447 from the Pacific coast, be- 

 sides the Siphonaria Lessonii which ranges from Valparaiso in 

 Chili to Maldonado on the coast of Uruguay, t These shells 

 belong to 110 genera, of which 55 are common to both coasts, 



* British Association Report for 1863. 



t The dispersion of this coast shell may perhaps have taken place at the time •when 

 the channel of the river S. Cruz formed a strait, joining the Atlantic and Pacific 

 oceans, like that of Mii^ellan. (Darwin, p. 181.) Mi-. Couthouy makes 3 ?.^.— Siphonaria 

 y.£/!.90Ht/, nearly smooth, Atlantic coast; ^. antarctica, ribbed, Pacific coast; and & 

 lateralis, thin, oblique, Fuegia. 



