MUSEUM OF COMPARATIVE ZOOLOGY. 41 



REPORT ON FOSSIL INVERTEBRATES. 



By Alpheus Hyatt. 



The Ammonitinae of the Cretaceous have been studied and 

 rearranged through the groups of Pseudoceratites and their im- 

 mediate allies, including also the Phylloceratidae and part of 

 Lytoceratidae. During the summer a number of species of Palae- 

 ozoic Cephalopods have been selected for exhibition. 



The Department is indebted to Dr. R. T. Jackson for revising 

 the collections of Pteropods, Lamellibranchs, Worms, and Bryo- 

 zoa, rearranging parts, and placing the whole in better condition, 

 and also selecting material suitable for exhibition. 



Part of the time of two Assistants has been expended in label- 

 ling and piecing together specimens of the Schary and other col- 

 lections, and also in mounting some fossils for exhibition in the 

 Stratigraphic Collection. 



Hon. C. D. Walcott and Hon. Frank Springer have looked over 

 parts of the collections, and selected materials to be sent them for 

 investigation, and the latter has donated a choice collection of 

 Palaeozoic Crinoids. 



Professor C. E. Beecher has given the Department some rare 

 Devonian Phyllopods, and a specimen of Triarthrus beckii show- 

 ing the appendages on the ventral side, and also his two beautiful 

 restorations of that species illustrating the final results of his suc- 

 cessful researches upon the external anatomy. 



A lot of fine Trilobites from the Middle Cambrian of Mt. Stephen, 

 British Columbia, has been presented by Messrs. F. N. Balch and 

 G. L. Paine. 



The superb work of Wachsmuth and Springer on 4 ' North Ameri- 

 can Crinoidea Camerata," in three large volumes, with eighty- 

 three plates, noticed elsewhere in the list of the Memoirs of this 

 Museum, has been partly based upon the materials accumulated 

 in this department, and shows the exceptionally rich character of 

 the collection of Crinoids. 



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