1890.] NATURAL SCIENCES OF PHILADELPHIA. 75 



south of the Tropics is very anomalous, l)ut future study of the 

 intervening regions may throw some light upon the subject. The 

 presence of the three species in the warm waters of the Mediterranean 

 is interesting, and worthy of note. 



Our present knowledge of the distribution of the species of the 

 genus may be summarized as follows : Arenicola marina, occurs in 

 the temperate seas of both hemispheres, and in the arctic seas of the 

 north ; Arenicola eeaudata is confined to the temperate seas of 

 Europe, and Arenicola cristata is found in the temperate and tropical 

 Atlantic, and in the ^Mediterranean. 



References to the complete literature of the subject will be found 

 in Quatrefage's " Histoire Naturelle des Anneles, " and in the papers 

 by Drs. von. Marenzeller and Horst, already referred to. 



