ALBINISM. 
15 
present as conjectural. Whatever be the real explanation, the 
facts shown by the specimens in this bay are very curious, and 
worthy of careful consideration. 
The next case on the east side of the middle of the hall Gronp ilius- 
contains a series of specimens illustrating albinism, a condition ^^^^^f 
n which the pigment, or colouring matter, usually present in 
Fig. 1. — The Leaf-Butterfly (Callima inachis) in Flight and at Rest. 
the skin, and giving the characteristic hue, is absent. Indi- 
viduals in this condition occur among many animals of various 
kinds, and are called " albinos'' In some of the specimens shown 
in the case the albinism is complete, but in many it is partial, 
the absence of colouring matter being limited to portions of 
the surface only. 
