Norwich Castle Museum. 143 
allusion to its mode of progression by leaps and 
bounds. The WraseE. (JZ. vulgaris) is much smaller 
than the Stoat, and the female, which is even smaller 
than the male, is called the ‘‘ Mouse-hunter.” All 
these are blood-thirsty little creatures, but of incalcul- 
able value in keeping down the rats and mice which 
form their favourite food. The Marten (artes 
foina), formerly common enough, is now a rare 
British animal, only surviving in woodland districts 
where the gamekeeper is not so much abroad as in 
this part of England. 
We must hope in time to receive specimens of the 
British RUMINANTIA, which are conspicuously 
absent, as also of the CETACEA, especially as the 
seas and estuaries of the Norfolk coast have proved 
exceptionally rich in species of the latter order. 
Cases |X. and X. 
The general collection of the animals forming the 
great class MAMMALTA, or those which give suck to 
their young, is so exceedingly fragmentary, that many 
very important sections are here quite unrepresented. 
Without going too much into detail, it may be said 
that the whole class can be divided primar'ly into 
three well-marked divisions, having no intermediate 
or transitional forms ;* these have been designated by 
Professor Huxley (1) Prototheria, (2) Metatheria, and 
(3) Lutheriaz, corresponding to the old divisions 
of Ornithodelphia, Didelphia, and Monodelpnia. 
The first of these divisions, the sub-class PROTQ- 
THERIA, comprises one order only, MONOTRE- 
MATA, consisting of two families, (1) ORNITHORHYN- 
* The arrangement is that adopted in Flower and Lydekker’s 
Introduction to the Study of Mammals, Living and Extinct. 
