THE BRYOZOAN FAUNA OF THE GALAPAGOS 



ISLANDS 



By Ferdinand Canu 

 Of Versailles, France 



AND 



R. S. Bassler 



Of Washington, District of Columbia. 



INTRODUCTION 



Continuing our investigations of the dredgings of the United 

 States Fish Commission steamer Albatross preserved in the United 

 States National Museum, we have recently completed the study of 

 the material collected from a few stations in the vicinity of the 

 Galapagos Islands. As a result we find that the bryozoa of the 

 Galapagos afford equally interesting results as other classes of 

 animals from this classic area. In the pursuit of these studies we 

 have had financial assistance from the American Association for the 

 Advancement of Science, which help is here gratefully acknowledged. 



Located on the equatorial line, the bryozoan fauna of the Galapagos 

 Islands is found to be particularly interesting to the paleontologist. 

 The species common with the Gulf of Mexico indicate the ancient 

 communication of the Pacific with the Atlantic and the very recent 

 formation of the Isthmus of Panama. These species are Acantho- 

 desia savartii, Aplousina fZum^ Callofora tenuirostris, Calloipora 

 curmrostris^ Cwpuladria umhellata^ Puellina innominafa^ Trypostega 

 venusta, Hippoporina deidostoTna, Mamillopora cuptila, and Liche- 

 nopora radiata. None of these is known to have made the circuit of 

 any of the continents, so that free communication between the two 

 oceans must have existed. 



Another remarkable phenomenon is the persistence in this region 

 of archaic forms laiown hitherto only as fossils and in which nat- 

 urally the anatomic structure was unknown. Very useful compari- 

 sons can thus be made by means of such species as Probosdna lamel- 

 lifera, Plagioecia subpapyracea^ Diaperoecia {ReticuUpora) mean- 

 No. 2810.— Proceedings U. S. National Museum, Vol. 76, Art. 13. 



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