INTRODUCTORY COLLECTION. 
23 
huge skull has undergone, and will show in the clearest manner 
to the least instructed visitor that the so-called fin or flipper of 
the whale is composed of all the same parts — shoulder, elbow, 
wrist, and fingers — as his own arm and hand. The hind limbs 
are entirely absent ; but two bones are seen suspended at some 
distance from the spinal column, which represent the pelvic or 
hip bones of other animals. In some species of whales there 
are even traces of the thigh, knee-joint, and leg attached to 
this, and like it deeply buried within the body of the 
animal. 
It is intended to place cases on the floor of the hall illustrat- 
ing general laws or points of interest in ITatural History which 
do not come appropriately within the systematic collections of 
the departmental series. 
One group, in a case placed at present near the entrance Group illus- 
to the hall, shows the great variation to which a species may y^^j^^^j^ 
become subject under the influence of domestication, as illus- under Domes- 
trated by choice exam^ples of the best marked breeds of Pigeons, t^^^^tion. 
all of which have been derived by careful selection from the 
wild Eock Dove {Columba livia), specimens of which are shown 
at the top of the case. 
A case placed on the left of this illustrates a remarkable Group of Rulfs 
instance of external variation in the two sexes and at different ^jj^g^^^^g 
seasons, not under the influence of domestication. The birds in external vari- 
it all belong to one species, the Euff (Machetes pugnax), of which f^^^to^g^ex^and 
the female is called Eeeve, belonging to the Snipe family season. 
(Scolopaddce). In the upper division of the case are shown the 
eggs, newly -hatched young, young males and females in the first 
autumn plumage, and old males and females in winter, when 
both sexes are exactly alike in colour, size only distinguishing 
them. The large group occupying the lower part of the case, 
consists of adult birds in the plumage they assume in the breed- 
ing time (May and June). In the female the only alteration 
from the winter state is a darker and richer coloration, but in 
the males there is a special growth of elongated feathers about 
the head and neck, constituting the " ruff," from which the bird 
derives its name. In addition to this peculiarity, another may 
be observed, which is rare among animals in a wild state (though 
so common among domesticated races), that of striking diversity 
