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 
Valparaiso. 
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 lable 
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 84 of the U. S. Geological Survey, pages 25-28, 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 unusual proportion of the species 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 particularly marked among the phytophagous 
groups. 
2. The fauna is notable for its Fissurellide and Acmeide, its 
Trochids of the genus Tegula, its numerous and peculiar chitons, its 
numerous Cancellarias, the development of Calyptreide, of species 
of Arcidee, and of the genus Thais, Ohione, Semele, Petricola, Mulinia, 
ail represented by numerous species. 
3. The deficiencies in the fauna are as marked as the redundancies. 
There are notably few Pectens or Lucinas, and the Tellinide are 
poorly represented. Acteon, the smaller Tectibranchs, Conus, the 
Turritide especially, the Marginellide, Fusinus and its allies, Epi- 
tonium (Scala) and the Pyramidellide are all very poorly repre- 
sented. Calliostoma and Margarita, Haliotis and Pleurotomaria are 
absent or barely represented. 
