THE MARINE FAUNA OF THE FALKLAND ISLANDS. 75 



(One species, an aberrant form, doubtfully referred to this genus, was 

 found in 2,600 fath.). 



The North Pacific region, 4 species, 10-30 fath. 

 ,, South ,, ,, 2 ,, one from 45 fath., the other 



from 1,325 fath. 



The genus is cosmopolitan, and appears to belong to shallow water, 

 yet evidence shows that it has a wide bathymetrical range. 



Cribrilina. This genus inhabits north and south temperate regions, 

 but only one species (C. Jioridana) has been recorded from the tropics 

 (Gulf of Florida). The genus is fossil, occuring in the French 

 cretaceous, Austro-Hungarian miocene (coral and red crag), Italian 

 pliocene, boulder clay (Wick). 



The species C. monoceros is notable in that it occurs in very shallow 

 as well as in very deep water. Off the west coast of the extreme south 

 of South America it has been found at a depth of 1,325 fath., in the 

 North Pacific at a depth of 3,125 fath., Strait of Magellan 25 fath., 

 Tierra del Fuego and Patagonia 19 fath., Cape Horn 40 fath, 

 Falklands 4-12 fath. My specimens were picked up on the beach. The 

 facts of its occurring in the tertiary deposits, its presence in the 

 north and south temperate regions, and its absence from the tropics, 

 tend to support Murray's argument, according to which Cribrilina may 

 be looked upon as a true representative of a primitive, universal, 

 marine, littoral fauna. 



On the other hand — and this is supported by the fact that this 

 species does occur in very deep water elsewhere — it may be that this 

 species exists in the tropics at great depths, and has thus escaped 

 capture. 



Lepralia. This genus occurs in the north and south temperate zones, 

 and within the tropics ; all the deep-sea forms occur in the temperate 

 regions ; the forms living in shallow water occur in the tropics as well 

 as in the temperate regions. This is rather interesting, for it shows 

 that the tropics do not form an insuperable barrier for all species, 

 between the two temperate zones. Then, again, according to Ort- 

 mann's view, one would expect to find the deep-sea forms nearer the 

 Equator, if the deep sea affords a passage between the two temperate 

 zones. 



The species L. adpressa occurs north and south of, but not within 

 the tropics, in shallow and moderately-deep water. It occurs fossil 



