36 AXEL A. OLSSON 



At the present time nearly 600 species of shell-bearing mollusks are 

 known from the coastal waters of Peru and Chile. Of this number, about 

 397 species or roughly 69 percent are Panamic-Pacific species which range 

 southward into Peruvian waters, the majority of which (about 53 

 percent) do not pass Punta Aguja. The overflow of some of these northern 

 forms south of Punta Aguja into the Peruvian faunal province is small and 

 most of these species are known only from its northern sector. Shells collected 

 at Lobos de Tierra, the most northerly of the two guano islands 

 just south of Punta Aguja, are largely the same species as found in Sechura 

 Bay at Bayovar. Lobos Island fauna, therefore, must be considered an 

 outlier of the Paita Buffer Zone. Several Panamic species occur at Lobos 

 Island and probably find their southern limit of range at that place, such 

 as Malea ringens, Fusinus dupetithoursi, Cancellaria chrysostoma, and 

 Cypraea cervinetta. It seems likely that these species do not extend much 

 further south. Mexicardia procera and Raeta undulata range south to Bahia 

 de la Independencia (lat 14° 15' S.) below Paracas. These vigorous north- 

 ern species are much larger in size than they attain along the coasts of 

 Ecuador and Panama. Semele corrugata, common at Paracas and Bahia, is 

 also common in the Paita Buffer Zone. Pecten purpuratus, the common 

 scallop of the Peruvian markets, is plentiful in Sechura Bay but is rare 

 north of the Gulf of Guayaquil. Concholepas concholepas is perhaps the 

 most characteristic species of the Peruvian Province. It seems to find its 

 northern limits at Lobos de Tierra, but all the specimens seen from there 

 are small. Oliva peruviana, Thais chocolata, and Turbo magnijicus are wide 

 spread and find their northern limits in the Paita Buffer Zone or in the Gulf 

 of Guayaquil. Amongst other characteristic Peruvian mollusks are Trochita 

 trochiformis, several large mytilids (Aulacomya, Choromytilus, Semi- 

 mytUus), and clams (Protothaca thaca and P. domheyi). The chitons are 

 numerous in the south, A cantho chiton echinata and Enoplochiton niger are 

 especially common, the former known also from Paita. Amongst the other 

 invertebrates are several species of barnacles, of which Balanus laevis is 

 especially common in the south, bunched in large clusters on boulders or 

 perched on the shell of Concholepas in a crowded mass. Of special interest 

 also along the coast of mid,dle Peru is a colonial polychaete worm {Gun- 

 narea) which forms large encrustations of closely packed, vertical, cal- 

 careous tubes. Such reeflike masses, often mistaken for coral heads, are 

 found in the Mancora tablazo at Paita and Cabo Blanco in northern Peru, 

 far north of their present-day known occurrence and show that these 

 Pleistocene deposits were laid down in waters as cool as those which now 

 wash the shore of Peru much further south. 



The deficiencies in the Peruvian fauna amongst the mollusks are as 

 striking as some of its redundances. There are no Tellinidae or Lucinidae. 

 Species of Conus and Terebra are lacking although a few forms are known 

 from Panama-Pacific and Paita Buffer Zones in northwestern Peru. 



The fauna of the Peruvian Province is one of temperate or relatively 

 cool waters and its penetration along the coast northward into the tropical 



