evidently highly favourable to rabbits, as proved by their extraordinarily
rapid increase, yet they differ conspicuously in their small size from the
wild English rabbit. Four English rabbits, measured from the incisors to
the anus, varied between 17 and 17 3/4 inches in length; whilst two of the
Porto Santo rabbits were only 14 1/2 and 15 inches in length. But the
decrease in size is best shown by weight; four wild English rabbits
averaged 3 pounds 5 ounces, whilst one of the Porto Santo rabbits, which
had lived for four years in the Zoological Gardens, but had become thin,
weighed only 1 pound 9 ounces. A fairer test is afforded by the comparison
of the well-cleaned limb-bones of a Porto Santo rabbit killed on the island
with the same bones of a wild English rabbit of average size, and they
differed in the proportion of rather less than five to nine. So that the
Porto Santo rabbits have decreased nearly three inches in length, and
almost half in weight of body. (4/24. Something of the same kind has
occurred on the island of Lipari, where, according to Spallanzani ('Voyage
dans les deux Siciles' quoted by Godron 'De l'Espece' page 364), a
countryman turned out some rabbits which multiplied prodigiously, but, says
Spallanzani, "les lapins de l'ile de Lipari sont plus petits que ceux qu'on
eleve en domesticite.") The head has not decreased in length proportionally
with the body; and the capacity of the brain case is, as we shall hereafter
see, singularly variable. I prepared four skulls, and these resembled each
other more closely than do generally the skulls of wild English rabbits;
but the only difference in structure which they presented was that the
supra-orbital processes of the frontal bones were narrower.

In colour the Porto Santo rabbit differs considerably from the common
rabbit; the upper surface is redder, and is rarely interspersed with any
black or black-tipped hairs. The throat and certain parts of the under
surface, instead of being pure white, are generally pale grey or leaden
colour. But the most remarkable difference is in the ears and tail; I have