27 



synopsis of the contents, so that any material may be as quickly 

 found as is practicable in the present condition of the collections. 

 This system admits of constant alteration and replacement of maps 

 and labels as the arrangement progresses, an obvious advantage 

 which does not need explanation. 



The Assistant has finished the systematic collection of Cephalo- 

 pods on exhibition, and a full presentation of the genera has been 

 given. The collections contain a very large proportion of the ori- 

 ginal types of all the genera yet described in this class, and of the 

 remaining genera good examples of all except a few recently pub- 

 lished in Europe. This exhibition is therefore probably the most 

 complete now in existence as an exposition of the range of natural 

 modifications in this important class of Fossils. 



The Sponges, Hydroids, and Echinoderms have been more or less 

 worked upon for the purpose of getting together all of the forms in 

 each genus, thus preparing the way for the permanent arrangement 

 and the final selection and naming of specimens for exhibition. 

 Some of the more important families of the Lamellibranchs in the 

 Jura and Cretaceous have been similarly treated, and are almost 

 completed. 



By the kind permission of Alexander Agassiz, Director, the 

 extensive foreign collections in the Trias and Jura of the Museum 

 have been placed at my disposal for the study and comparison of 

 our American species with the typical European forms. The great 

 advantages thus gained will be appreciated by all professional palae- 

 ontologists, especially those engaged in similar work, but obliged 

 to rely solely upon foreign publications. These collections will 

 require considerable time to bring them into proper shape for this 

 purpose, since much of the material has been acquired in separate 

 lots from different collectors, and needs to be concentrated and 

 arranged. This work has been begun and an appreciable advance 

 made during the past year. 



Besides efficient services in connection with the general arrange- 

 ment and superintendence of the removal and placing of fossils, the 

 department is indebted to Dr. R. T. Jackson for a large amount 

 of work in the revision of the Mollusca, Corals, and Brachiopods, 

 which contained unarranged material and considerable special work 

 upon some smaller groups. 



Miss Clark has been employed in preparing labels, and dusting 

 and remounting specimens. It became necessary to remount a very 



