130 The Irish Naturalist. [June, 



the dentition of a horse. The advantages of a study of the 

 latter will appear when it is remembered that horse-breeding is 

 much favoured in Ireland, and the difficulties of telling the 

 age (say between four years and five years) are very great 

 indeed. Blaschka's models of various invertebrate types, 

 Fritch's elegant dissections, and some special casts of viscera 

 serve to illustrate forms that are not alwaj r s available in 

 a fresh condition. The collection of dried plants and fruits 

 is of the ordinary kind. 



The apparatus for illustration include a series of panoramic 

 diagrams on rollers, that enable the student to see the figures 

 in a progressive series, and save much trouble to assistants in 

 arranging drawings for demonstration. An apparatus for 

 determining the rotation of limbs consists of a frame with a 

 graduated circle, by which the amount of rotation and its 

 character can be understood. A vertical shaft that carries 

 framed diagrams is a useful apparatus ; the latter is in use 

 elsewhere, especially in picture galleries. A microscope with 

 a revolving platform is one of the most satisfactory instruments. 

 Specimens can be examined in succession by turning a handle. 

 The instrument is enclosed in a box so that it cannot be injured 

 in any way by a visitor or an observer. One case is of very great 

 interest — the case of disarticulated skulls. These are of great 

 value in the study of the size and distribution of the bone bars 

 and plates in the skulls of different groups ; such skulls can 

 be advantageously compared with those that are intact or with 

 special sections. 



Stopping for a moment to mention the groups of birds' 

 nests and eggs, a combination may be mentioned that 

 partakes partly of the nature of a laboratory, a biological 

 cabinet, and a museum, viz., the preservation of a few living 

 invertebrates in suitable bottles or cages. 



Proximity to the sea makes it possible to secure quite a 

 number of specimens. These can be renewed from time to 

 time. Young people at Salthill, Galway, obtain a hetero- 

 geneous collection on the shore, and the movements and 

 activities are watched for hours with much interest. Many 

 other varieties obtainable on the land are not sought after 

 with so much avidity. 



