Lucas.] 
228 
[October 
to the water-tiger, as I shall have occasion to show in another 
paper, and it may here he remarked that the pharynx in insects 
should be defined as the muscular portion of the alimentary canal 
between the mouth and the oesophagus, which is hung in the 
cranium by special suspensory muscles ; it therefore resembles 
the rectum at the opposite end. of the alimentary tract, like- 
wise muscular and often suspended by muscles from the abdom- 
inal walls. 
In conclusion we find that the water-tiger, far from being mouth 
less as ordinarily assumed, has in fact a very wide mouth, though 
its lips are closely locked together by a dove-tailed groved joint 
developed for this purpose. Whether this joint can be unlocked 
by the animal itself, is another question, which I cannot answer- 
though De Geer’s observation, above quoted, makes this probable. 
It is at all events easy to open the mouth by manipulation with 
a pair of forceps. 
THE SPECIES OF ORANGS. 
BY FREDERIC A. LUCAS. 
The number of species of Orangs has been placed variously at 
from one to four, and the examination of the series of skulls on 
which this article is based was undertaken with a view to ascertain 
ing just how many valid species existed. Prof. J. A. Allen long 
ago expressed his belief that a careful investigation would prove 
that the various species had been formed from specimens of differ- 
ent ages, and but for him this paper would never have been writ- 
ten, my own opinion being that there were two good species. 
Thus while I am pleased to testify to the correctness of Professor 
Allen’s prediction I can hardly be accused of having worked up 
to a predetermined result. My thanks are due to Prof. Henry A. 
Ward, who placed the large collection of Orangs in his possession 
at my disposal, and to Mr. Wm. T. Hornaday who furnished me 
with important data from his notes taken while collecting Orangs. 
The various so-called species may be briefly described as 
follows : 
