12 



Haven, Xantueket and AVood's Holl, and it extends as far 

 south as the shores of Ehjrida. 



From the above remarks it will be noted that Anurkhi 

 marithiKi is a form ranging into both the Pakearctic and 

 Xearctic regions. This wide distribution of an animal 

 with practically no means of self-dispersal is remarkable. 

 Folsoni (63) believes that marine currents have been the 

 principal agents for its distribution. They would 

 certainly account for its presence on the barren rocky 

 islands off the Scandinavian coast and at Helio-oland and 

 the Isle of Man. 



An allied terrestrial S2)eeies, Anurida (Aphoroinina) 

 (/i-anaiid. (Xic), has likewise a very wide geographical 

 distribution. It has a very extensive range in Europe, 

 being known from Grreat Britain, France, Scandinavia, 

 the Tyrol and Bohemia, and it is also recorded in Arctic 

 regions from Spitzbergen, Franz-Tosef Land and North 

 Siberia. ^4. tuUhergi, Schott, w^hich frequents the surface 

 of ponds of fresh water, is found in northern Europe and 

 has also been recorded from the United States. Another 

 species, A. clavata, Scliaif., is found in Tierra-del-Fuego ; 

 A. amorita, Fols , is known from Alaska and Siberia, and 

 A. steineni, Schiitf, is a South Georgian species. 



IY._MORPHOLOaY. 



1. GrENEKAL FEATURES OF ExTEKNAL AnATOMY. 



The general appearance of Anuridd when viewed 

 under the lower power of the microscope will be seen on 

 referring to fig. 1. As in all insects, the body consists of 

 three well defined regions, viz., the head, the thorax and 

 the abdomen. Its exo-skeleton is but feeblv chitinised, 



