4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



Hungary 



Budapest: Hungarian Geological Institute: Dr. Erzsebet Szorenyi, Dr. 

 Jozsef Fulop. 

 India 



Calcutta: Geological Survey of India: Dr. V. R. Khedker. 

 Poland 



Warsaw: Polska Akademia Nauk: Dr. Gertruda Biernat. 

 Portugal 



Lisbon: Servigos Geologicos de Portugal. 

 Sicily 



Palermo: Istituto di Geologia: Dr. Giuliano Ruggieri. 

 Switzerland 



Basel : Naturhistorisches Museum : Dr. E, Gasche, Dr. Hans Kugler. 

 Geueve: Museum D'Histoire Naturelle: Dr. E. Lanterno. 

 Zurich : Geologisches Institut : Dr. R. Trumpy. 

 U.S.A. 



Austin, Tex. : University of Texas : Dr. Keith Young. 

 Baltimore, Md. : Johns Hopkins University : Dr. David Raup. 

 Berkeley, Calif. : University of California : Dr. J. Wyatt Durham. 

 Cambridge, Mass. : Harvard University, Museum of Comparative Zoology : 



Dr. Harry B. Whittington, Dr. E. Deichmann. 

 Chicago, 111. : Chicago Natural History Museum : Dr. Eugene S. 



Richardson, Jr. 

 Ithaca, N. Y. : Paleontological Research Institution : Dr. Katherine Palmer. 

 New York, N. Y. : American Museum of Natural History : Dr. Norman D. 



Newell. 

 Philadelphia, Pa. : Academy of Natural Sciences : Dr. Horace G. Richards. 

 San Francisco, Cafif. : California Academy of Sciences : Dr. Leo G. 

 Hertlein. 

 U.S.S.R. 



Leningrad : Geological Museum of the Academy of Sciences of the U.S.S.R. : 



Dr. Z. Krjachkova. 

 Moscow: The Palaeontological Institute of the Academy of Sciences of 

 the U.S.S.R. : Dr. J. Orlov. 



EVOLUTION 



AMBULACRAL PORES 



There is a striking example of parallel evolution in the ambulacra 

 of the cassiduloids. In the species occurring before the Cenomanian, 

 there are pore pairs in all the ambulacral plates, but in all those oc- 

 curring after the Senonian, there are only single pores in the ambu- 

 lacral plates beyond the petals. This change is graphically shown in 

 chart I, in which all the genera below the bold line have double pores 

 beyond the petals, and all those above this line have a single pore. 

 That such a change was forthcoming is indicated by the reduction in 

 size in one of the pores of a pore pair in many pre-Cenomanian and 



