LINNEA>f SOCIETY OF LOXDOX. 85 



Local geologists class the stratum in which it occurred as Eocene, 

 but English and American geologists are less disposed to grant 

 these beds such antiquity. 



If marsupials had not been available, the case could have been 

 made as clear from herpetological evidence. And, indeed, were 

 the vertebrata disregarded, the liypothesis could still be as well 

 established from the invertebrata or the plants. 



Among the reptiles, fifty genera of the Iguanidse are known, all 

 of which are confined to the New World, chiefly South America, 

 except one genus in Eiji and two in Madagascar. Australian 

 snakes are divisible into the venomous and the non-venomous 

 groups. All the venomous are of the family Elapidae, related to 

 South American types ; they focus in Tasmania, where non- 

 venomous snakes are absent. The non-venomous snakes are of 

 Asiatic or Papuan alHnity, and focus in North Queensland. The 

 majority of Austx'alian frogs are also akin to South American 

 forms. 



A family of large snails, conspicuous for the size and beauty of 

 the shell and distinct in structural features, called by Dr. Pilsbry 

 the Ilacroogona, has the following distribution : — In South 

 America, chiefly tropical, Macrocyclis 1 species, Strophochilus 

 51 species, and Goni/ostomiis 5 species ; in Madagascar, Ampelita 54 

 species and Helicophanta 16 species ; in the Seychelles, Stijlodonta 

 2 species ; in Ceylon, Acavus 7 species ; in the Moluccas, Pyro- 

 chihis 4 species ; in Tasmania, Anogh/pta 1 species and Cart/odes 

 1 species ; in Eastern Australia, Pedinogyra 1 species and Panda 

 4 species. The Chilian Macrocyclis and the Queensland Pedinogyra 

 by shell characters pair together, while Helicophanta is a match 

 for Panda. The absence of this family from New Zealand, its 

 preponderance of species in Madagascar, of genera in Tasmania 

 with Australia, and its development in the tropics are remarkable 

 characters of this old austral group. 



The snail family Bulimulida^ is chai'acteristic of South America, 

 beyond which two genera stray into the West Indies and North 

 America, and two others, Botliriemhryon and Placostylus, occur in 

 Australasia. The first ranges from Tasmania to AVest iVustralia, 

 and forms an exception to Antarctic rule by liaving its distri- 

 bution centre in the latter. Indeed, Botliriemhryon and the 

 fluviatile crustacean Gha'raps raise a suspicion that West 

 Australia had direct relations with Antarctica, prior to and 

 independent of the Tasmanian Istlimus. Placostylus extends from 

 New Zealand to Fiji and New Guinea, "giving testimony," as 

 Pilsbry remarks, "to the foi'mer existence of an Antarctic land 

 connecting the austral continents of the two hemispheres " (Man. 

 Couch., Index, vols. x,-xiv. 1902, p. ix). 



The Buprestidaj, a family of large and handsome beetles, exhibit 

 a striking affinity between Australia and South America. So 



