ZOOLOGY. 369 
tremity was bifurcated, beyond which there were two sets of 
viscera. i 
The cranial cavity was divided by a cartilaginous septum which 
separated the two sets of brains. Each set of spinal nerves entered 
its division of the cranium through its own foramen magnum. 
The cranial bones were normal in number and appearance save the 
occipital, which had two openings for the spinal nerve, each side 
of the median line, and processes for muscular attachment. The 
optic cavities were imperfectly formed. The eyes were not devel- 
oped, a bundle of fascia with some nerve substance occupying 
their place. 
The subject having been frozen and refrozen several times be- 
fore it came into my possession, I was unable to pursue the anatom- 
ical investigation of the several structures to the extent that 
I desired, such processes having destroyed the cranial ganglia 
and nervous system, the microscope revealing the disorganized 
structures. 
These hogs evidently had their origin in one ovum, with two 
nuclei or germinal centres situated equidistant from one another, 
and not from two ova which had become nucleally and anatomi- 
: cally commingled in the course of their development.—T. W. 
‘Degrine, M. D., Leavenworth, Kansas. 
Swarminc or A Broop or Wincep Ants.—On the afternoon of 
Oct. 6th, at about 4 P. M. we were attracted to a part of the large 
yard surrounding our home, by a multitude of large sized insects ` 
that filled the air, and appeared to be some unusual form of insect 
life, judging of them from a distance. On closer inspection, 
these creatures proved to be a brood of red ants (Formica) that 
had just emerged from their underground home and were now 
for the first time using their delicate wings. The sky, at the time, 
was wholly overcast; the wind strong, southeast; thermometer 
66° Fahr. Taking a favorable position near the mass, as they 
slowly crawled from the ground, up the blades of grass and stems 
of clover and small weeds, we noted, first, that they seemed dazed, 
Without any method in their movements, save an ill-defined impres- 
Sion that they must go somewhere. Again, they were pushed 
forward, usually, by those coming on, after them, which seemed to 
add to their confusion. As a brood or colony of insects, their 
every movement indicated that they were wholly ill at ease. 
AMER. NATURALIST, VOL. VII. 24 
