KEPOET OF ASSISTANT DIRECTOR. 45 



rangement of the exhibition series of vertebrate skeletons was eftected. 

 A month later the entire collection of bird skeletons was brought from 

 the Smithsonian building and stored in the exhibition hall. An arrange- 

 ment was made with the authorities of the Army Medical Museum for the 

 exchange of a collection of human skulls for skeletons and skulls of North 

 American vertebrates, and in April the first installment, consisting of 

 about 500 skulls and 350 skeletons of North American vertebrates, was 

 transferred to the TJ. S. National Museum.* In April an agreement was 

 entered into between the Army Medical Museum and the National Mu- 

 seum to undertake post-mortem examinations of animals in the flesh 

 received by the Institution, and of which the donors desire to know the 

 cause of death. Under this arrangement it was agreed that the viscera 

 of such animals should become the property of the Armj^ Medical Mu- 

 seum, the skeletons, unless otherwise specified, to be returned to the 

 National Muiseum. A series of casts of bones of Binoceras, presented 

 by Prof. O. C. Marsh, was placed on exhibition. One of the most in- 

 teresting of the recently exhibited skeletons is that of Bhytina gigc^e, 

 obtained by Dr. L. Stejneger for the Institution in Bering Island. 

 Some progress has been made in the preparation of a series of speci- 

 mens illustrative of the modifications of the limbs and other portions 

 of the skeletons in the different classes of vertebrates. Experiments 

 in special cases for the exhibition of this and other similar series have 

 proved very successful. But little work has been done in connection 

 with the reserve series, except for the purpose of ascertaining that the 

 specimens are in good order. 



if) Department of Mollusks, 



This department has been making extraordinary progress under the 

 charge of Mr. William H. Dall, assisted by Dr. E. E. C. Stearns. Mr. 

 Dail reports that the department under his charge has been making 

 steady advance in its administration upon the mass of accumulations of 

 the last ten years, and, except in regard to the New Orleans exhibit, has 



* Summary of specimens received from Army Medical Mustum. 



The curator reports that while this showing is good in quantity, yet the quality is 

 very poor. The larger crania are good, or fairly so ; but a large part of the smaller 

 skulls are imperfect and not clean. The skeletons are all small and united by natural 

 ligaments. None were in sufficiently good shape to be placed on exhibition, and owing 

 to the methods of preparation they cannot be now cleaned. They may eventually be 

 used to break up for study specimens, but that is their only value. 



