1597.] Zoology. 79 
‘two dates. The dates 1840, 1834, 1835, are the earliest at which the 
‘enumeration of the groups opposite them was made. Of course the 
sum 366,000 will not be recognized as complete by the student of 
fatinistics, who will claim that many valid species have been described 
that are not mentioned in the Zoological Record, and if we take 
estimates into consideration, it may be noted that the late Dr. C. V. 
Riley estimated that 10,000,000 would not be too great a number to 
represent the probably existing species of insects alone. If this be a 
fair estimate for the one group, insects, then, since they seem to 
represent about two-thirds of the whole, a reasonable estimate for the 
whole animal kingdom would be about 15,000,000 of species. But at 
the same time that this estimate is considered, it should be noted that 
the facts brought to light within the last few years by students of the 
mechanics of ontogeny and especially by such experiments as those 
made by Weismann and others in studying the seasonal dimorphism of 
of Lepidoptera indicate that very many of the species hitherto 
regarded as valid may be far from valid, and that descriptions of 
species in the future unless they are based upon a long series of 
experiments are apt to be much more uncertain than before. 
F. C. Kenyon. 
The Terceira Dog.—While many other dogs of various breeds 
are seen in Terceira, the yellowish-brown bull dog, often with black 
face, is so abundant as to be recognized as the characteristic dog of the 
island. Commonly it stands some two feet high, and while often gentle 
is frequently very savage. It is said that those intended for watch dogs 
are trained to jump at a hat held in the hand, in this way learning to 
spring at a person they attack. When kept chained, and not fondled, 
they will attack any person approaching, even refusing to recognize 
their master at night in many cases. 
Usually the ears are trimmed round, and the short, deformed tail is 
docked to a stub, so that these marks are almost as characteristic as 
those which are hereditary. 
Occasionally a dog of this breed is seen on the other islands, Madeira, 
or the continent, but all that I have ever seen were originally derived 
from Terceira, and are called Terceira dogs by the Portuguese. The 
group of these dogs accompanying (Plate V), I owe to Mr. A. E. Cady, 
of Providence. The single animal I took with a Kodak on aship in the 
islands— Wm. TRELEASE. 
