NO, 13 COE : REVISION OF THE NEMERTEAN FAUNA 249 



The Peruvian littoral fauna is evidently more closely similar to 

 that of Chile and Patagonia than to the tropical zone on the northward, 

 presumably because of the colder southern waters which flow northward 

 adjacent to the coast. The entire region south of Ecuador would thus 

 comprise a sixth faunal zone. 



The collections of the Allan Hancock Expeditions included the south 

 central and southern of these 5 faunal zones and the coast of Peru. The 

 known southern range of a considerable number of species has been 

 thereby greatly extended. For the reasons stated above, however, the 

 species of all zones will be grouped together into a comprehensive list 

 which will give also the geographical distribution of each species as 

 far as at present known. Table 1 will indicate the numer of species of 

 each of the genera which have been found in each zone up to the year 

 1939. 



In the geographical distribution as given for each species specific 

 localities, if numerous, will be indicated only by the limits of the known 

 range. 



Bibliographic references to species described previous to the publi- 

 cation of the monograph of 1905 will not be repeated in the literature 

 list to be found at the end of this report. 



In the synoptic keys which are given for the determination of families, 

 genera, and species, only those groups and species are included which are 

 known to be represented on the North Pacific coast from Ecuador to the 

 Arctic Ocean. Hence, such of the Peruvian species obtained by the Allan 

 Hancock Expeditions as are not also known to occur north of the equator 

 are included only in the descriptive lists of species. 



