34 



REPORT ON THE PALiEONTOLOGICAL 

 DEPARTMENT. 



By Alpheus Hyatt. 



The Trigoniidse, Ostreidse, Pinnidae, and some other families 

 of Lamellibranchs, have been worked over with greater or less 

 care, and materials selected for exhibition. 



A large amount of miscellaneous work, which cannot be re- 

 ported upon specifically, has been done in order to prepare the 

 way for the selection of materials to be placed upon exhibition. 

 The Senary, Day, Dyer, Walcott, and other collections of Silu- 

 rian and Devonian Brachiopoda have been similarily treated, 

 the genera brought together, and the materials picked out for 

 exhibition. 



The enormous number of specimens in these collections, and 

 the fact that the same species frequently appears under different 

 names, and the same genus in one collection may be split up into 

 half a dozen genera in another, makes such work more tedious 

 and difficult than had been anticipated. Before the specimens 

 selected for exhibition are finally labelled, it will be necessary to 

 revise the generic names to avoid confusion. 



As in previous years, the department has had the benefit of 

 the labors of Dr. R. T. Jackson. He has distributed the Triassic 

 and Permian collections reported upon last year as still intact, 

 and therefore all the Fossil Invertebrata are, with the exception 

 of one tier of cases reserved for slabs and miscellaneous materials 

 in Room A, arranged zoologically as described in the last An- 

 nual Report. He has also done considerable work in various 

 departments which cannot be reported upon in detail, and has 

 distributed into their proper genera a large number of Tertiary 

 Lamellibranchs. 



