190 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.37. 



253 species common to the Panamic Province and to Peru, and 239 

 species of the Panamic Province which are known to reach the 

 northern border of the Peruvian Province at or near Cape Blanco, 

 many of which will doubtless be found to have a more extended 

 southerly range. In addition to these there are 25 species whose 

 range extends from Upper California south to Peru or even to 

 A^alparaiso. 



At the southern extreme of the Peruvian Province it receives 41 

 recruits from the Magellanic Province, few of which range north of 

 Valparaiso. Of the whole 805 species enumerated, which are not 

 pelagic, only 24 are known from the West Indies or Atlantic Ocean, 

 most of which are Pholads, borers, or limpets, forms peculiarly liable 

 to transportation long distances on ships or floating timber. The 

 only species which can be regarded as also Indo-Pacific are even 

 fewer in number and to be included in the same category. 



Eliminating all the pelagic species and all the Panamic species not 

 shown to be now actually domiciled within the limits of the Peruvian 

 Province, we have a population for the province of 566 species of 

 littoral marine mollusks. 



In Bulletin S4 of the V. S. Geological Survey, pages 25-2(S, 1892, 

 I have shown that the average population for a warm-temperate 

 area (where the temperature ranges from 60° to 70° F.) is about 

 500 species of shell-bearing mollusks. Adding the species of Nudi- 

 branchs, naked Tectibranchs, and littoral cephalopods enumerated 

 in our list, it would seem that the average is pretty well maintained 

 in the case of the Peruvian Province. 



Dismissing the minuter species from consideration as insufficiently 

 known, the more striking characteristics of the Peruvian fauna may 

 be summed up as follows: 



1. There is an uiuisual j)ro})()rtion of the s])ecies which are black 

 or blackish or of a lurid tint. This feature of the fauna has attracted 

 attention from all who have studied it and has been discussed by 

 von Martens. It is particulaily marked among the ])hytophagous 

 groups. 



2. The fauna is notable for its Fissurellidae and Acmseidfe, its 

 Trochids of the genus Tegula, its numerous and peculiar chitons, its 

 numerous Can(;ellarias, the development of Calyptrteidje, of species 

 of Arcidffi, and of the genus Thais, Cliione, Semele, Petricola, Ilvlinia, 

 all represented by numerous species. 



3. The deficiencies in the fauna are as marked as tlie redundancies. 

 There are notably few Pectens or Lucinas, antl the Tellinidse are 

 poorly represented. Acteon, the smaller Tectibranchs, Conus, the 

 Turritidae especially, the Marginellidse, Fusinus and its allies, Epi- 

 tonium {Scala) and the Pyramidellidse are all very poorly repre- 

 sented. Calliostoma and Margarita, Haliotis and Pleurotomaria are 

 absent or barely represented. 



