The Scottish Naturalist. 103 



models have been largely made use of to illustrate such parts of 

 the animals as are not easily preserved in a dry state, as well as 

 to demonstrate their structure and development. Preparations of 

 the shells show the internal structure, e.g., the internal form of 

 the spire in univalves, and the attachment of the muscles in 

 bivalves. Their geological history is also shown, so far as space 

 permits, by examples of extinct species. It should have been 

 said that this has been done in the other sub-kingdoms also. 



Twelve trays may at first sight seem quite inadequate to illus- 

 trate a sub-kingdom containing so many large forms as the Verte- 

 brata, but a little consideration will show that even in this space 

 it is possible to exhibit the essential characters of the five Vertebrate 

 Classes ; and that in a small museum it is not advisable to do 

 much beyond this. We need not describe the treatment of the 

 Classes separately, since, for the ease of comparison, they are 

 illustrated in a somewhat similar manner throughout. In each 

 there is a perfect skeleton shown, and along with it are specimens 

 to show the nature of the integument and its covering ; and, as far 

 as space allows, typical species of each group are shown. Models 

 of brains and of the hearts with the large vessels are placed in the 

 case; while dissections in fluid, with the bloodvessels injected, 

 demonstrate other details. The younger stages of the lower 

 Classes are illustrated by examples. Any remaining space is de- 

 voted to instructive specimens, such as skulls with the different 

 bones coloured and named. It is intended to show by coloured 

 crania, when these can be procured, the system of classification 

 now generally adopted for birds, which depends on the form of 

 the vomer and palatine bones. 



A whole table-case is allotted to the Botanical index collection. 

 Of the twenty-four trays in it, fourteen are occupied by the Flower- 

 ing Plants or Pha7ier ogams. In these are shown, as far as possible, 

 the form and structure of the various parts of the plants, the 

 specimens being supplemented by drawings. Thus we have the 

 forms, normal and abnormal, of roots and stems, both recent and 

 fossil, illustrated by sections longitudinal and transverse, and by 

 drawings of the microscopic structure ; so that the differences 

 between exogenous and endogenous stems is well exhibited. The 

 lower divisions have not been entered on however. Other trays 

 contain preparations and dissections of the leaves and flowers, 

 supplemented largely by drawings to exhibit the nature of those 

 parts too small to be seen with the unaided eye in the actual 

 specimen. A series of trays is devoted to the various forms of 

 seed-vessels and fruits, concluding with examples to demonstrate 

 the seeds and their inner structures. 



To the Pteridophyta, or Ferns and their allies, three trays are 

 given, beginning with drawings to show the processes of reproduc- 

 tion in the group, and followed by types of the different plants com- 

 posing it, both recent and fossil, illustrated by specimens. The 



