Caepkntee and Phillips — Collemhola of Spitsbergen. 15 



Archisotoma is one of the most distinct and interesting forms of the order, 

 belonging essentially to the tide-mai'k fauna, and with a range around the 

 North Atlantic coasts, both east and west. It may probably be regarded as 

 belonging to the same American-West European geographical group as the 

 sponge Heteromeyenia Ryderi and the well-known American plants of 

 western Ireland ; its presence in Greenland and Jan Mayen, and its 

 apparent absence from the Asiatic Arctic districts, are suggestive in this 

 connexion. It reappears far southwards in Tierra del Fuego ; and a closely 

 allied species A. Brucei (Carpenter, 1906) inhabits the South Orkneys in the 



Antarctic Ocean. 



Agrenia Borner. 



Agrenia bidenticulata (Tullberg). 



Isotoma lanuginosa Carl (1889). 



This distinct northern and Alpine springtail is sparingly represented in 

 the collection. Prince Charles Foreland (two specimens among decaying 

 seaweed on shingle shore, inner side of Kichard Lagoon, 9th July, 1921 ; 

 four specimens on snow slope, side of hill, 10th July, 1921) ; Cape Boheman 

 (three specimens on surface of pond in rocks of tundra near coast, 12th July, 

 1921) ; Klaas Billen Bay (two specimens on side of Mount Terrier, height 

 2,800 feet, 29th July, 1921). A. bidenticulata is recorded by Skorikow (1900, 

 p. 205) from the southern end of "West Island (Horn Sound, Batty Bay, and 

 Whales Bay), as well as from Genevra Bay, east of the Island, and from 

 King Karl Islands. 



Agrenia iidenticulata has a wide range in the Arctic, including Franz 

 Josef Land and Greenland ; but it is apparently unknown on the American 

 continent. In Europe it is found in Norway and Finland; and one may 

 detect it beneath stones in the bed of mountain streams in the Irish and 

 North British highlands. Apparently absent from the central European 

 plain, it reappears in the Swiss Alps, on the edge of the melting snows in 

 springtime (Carl, 1899, pp. 307-10). 



Isotoma Bourlet. 

 Isotoma viridis Bourlet. 

 This widespread insect was found by the Expedition at a larger number 

 of localities than any other, though it is apparently less abundant in 

 individuals than Proisotoma Beselsi. It occurs on Bear Island as well as on 

 the Spitsbergen archipelago {sens, str.) ; Tullberg (1876) recorded it from 

 both many years ago. All the specimens collected are of the " self-coloured " 

 aspect regarded as " typical " for this species ; but the colour of individuals 

 varies from bright green to dark olive, or from clear violet to deep blue- 



