24 CENTRAL HALL. 



to display not only the shape of the crowns, but also the 

 number and character of the roots by which they are implanted. 

 Bay II. In bay No. II. the two wall-cases contain a collection ar- 



Classification ranged to show in a serial manner the generally recognised 

 orders and sub-orders of existing Mammals, by examples 

 selected to illustrate the predominating characters by which 

 these are distinguished. A brief popular account of the 

 characteristics of the group, and a map showing its geographical 

 distribution, are placed with each. This is intended not only for 

 an introduction to the study of the class by visitors to the 

 museum, but also as a guide to a method of arrangement which 

 may be adopted in smaller institutions. 



Among the illustrations of the order Primates is placed the 

 skeleton of a young Chimpanzee dissected by Dr. Tyson, 

 which formed the subject of his work on the "Anatomy of a 

 Pigmie," published in 1699, the earliest scientific description 

 of any Man-like Ape. 

 Skin The central case of this bay contains illustrations of the 



amma s. Q^j.gj. covering or skin and its modifications in the class 

 of Mammals, divided into the following sections : 



1. Expansion of skin to aid in locomotion, as the webs 

 between the fingers of swimming and flying animals, the para- 

 chutes of flying animals. 



2. The development of bony plates in the skin, found among 

 Mammals only in the Armadillos and their allies. The cast 

 of a section of the tail of a gigantic extinct species 

 (Glyptodon) shows a bony external as well as an internal 

 skeleton. 



3. The outer covering modified into true scales, much resem- 

 bling in structure the naUs of the human hand. This occurs 

 in only one family of Mammals, the Pangolins, or Manidce. 



4. Hair in various forms, including bristles and spines. The 

 two kinds of hair composing the external clothing of most 

 Mammals, the long, sttffer outer hair, and the short, soft under- 

 fur, are shown by various examples. 



5. The special epidermal appendages found in nearly all 

 Mammals on the ends of the fingers and toes, called according 

 to the various forms they assume, nails, claws, or hoofs. 



6. The one or two unpaired horns of the Ehinoceroses, shown 



