1898] GEOGRAPHICAL DISTllIBUTION OF ACTINIAIUA 105 



the problems bearing upon the uiigrations of the terrestrial mammals 

 of Cretaceous and Tertiary times. Professor E. T. Hill., of the American 

 Geological Survey, is at present engaged upon a comparative study 

 in the field of tlie geology of tlie various West Indian Islands and 

 that of the mainland ; his results in this connection will be awaited 

 with interest. 



Although the Caribbeo-Pacific region is so distinct in its 

 general facies, suggestions are not wanting of an admixture of certain 

 Mediterranean forms. Previously known from the latter locality by 

 only a single species, the genus Banodcopsis has now been increased 

 by two closely allied forms discovered in Jamaica. Living as the 

 polyps do, attached to the leaves of marine plants such as Posidonia, 

 Zostera, TJicdassia, and Riq^pia, which are often uprooted and float 

 long distances, we can readily conceive of their travelling along with 

 the equatorial currents from the one continent to the other. On 

 such an explanation we may expect to find similar species around 

 islands which, like Madeira and the Canaries, lie in the course of 

 these currents. The occurrence of the allied genus Alicia in the 

 Mediterranean, at Madeira, and at Panama, as well as at Fiji and 

 Torres Straits, may perhaps be accounted for in some such way.^ 



Such instances must probably be looked upon as dependent on 

 peculiar or accidental circumstances and not as interfering with the 

 broad distinctions already laid down. J. E. Duekden. 



1 Mr J. Y. Johnson states that A. mirabilis frequently changed its position in con- 

 finement and may even float base upwards. Its vesicles also would assist it in floating. 



Referexces. 



"07. Sloane, Sir Hans. — A Voyage to the Islands Madeara, Barbadoes, Nieves, St 



Christophers and Jamaica, etc. 2 vols. (vol. ii.; 1725), London. 

 '34. Ehrenberg, C. G. — Die Korallthiere des Rothen Meeres. Berlin. 

 '60. Duchassaing, P. et Michelotti, J. — Memoire sur les Coralliaires des Antilles. Mem. 



EeaJc Arcad. iJi Torino, 2, xix. 

 '66. Duchassaing, P. et Michelotti, J. — Supplement au McSmoire sur les Coralliaires des 



Antilles. Ibid., 2, xxiii. 

 '69. Verrill, A. E. — Review of the Corals and Polyps of the West Coast of America. 



Trans. Conned. Acad. I. (1868-1870). 

 '77. Klunzinger, C. B. — Die Korallthiere des Rothen Meeres. I. Alcyouaria und 



Malacodermen. Berlin. 

 '89. McMurrich, J. P. — The Actiniaria of the Bahama Islands, W.I. Journ. Morph., 



vol. iii. 

 'S9a. McMurricli, J. P. — A Contribution to the Actinology of the Bermudas. Proc. 



Acad. Nat. S'ci. Philad. 

 '93. Saville-Kent, W. — The C4reat Barrier Reef of Australia. London. 

 '93. Haddon, A. C, and Sliackleton, A. M. — Description of some New Species of 



Actiniaria from Torres Straits. Proc. Roy. Dubl. Soc, vol. viii. (n.s. ), part I. 

 '96. McMurrich, J. P. — Notes on some Actinians from the Bahama Islands, collected by 



the late Dr J. J. Northrop. A)in. N.Y. Acad. Sci., July. 

 '96. Haddon, A. C, and Duerden, J. E. — On some Actiniaria from Australia and other 



Districts. Trans. Pay. Dubl. iS'oc, vol. vi., ser. 2. 

 '97. Duerden J. E. — The Actiniarian family Aliciidae. Ann. Mag. Nat. Hist., vol. xxi., 



July. 



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