NATURE’S TRANSFORMATION AT PANAMA 
it, it became so wild on my approach as 
to prevent any. further study; but as this 
particular monkey has not a prehensile 
tail and the eyes and general features re- 
semble the lemur, a strictly nocturnal ani- 
mal, it is probable that it represents a 
connecting link between the monkeys and 
the lemurs. 
A HUNTER FOOLED 
In the North I had found that the eyes 
of one species of night-hawk, belonging 
to the goatsucker family, would shine 
brightly under the light. While at Gatun 
I at once noticed that the night-hawks 
circling about the electric lights after in- 
sects had very brilliant eyes, and on one 
occasion, when Mr. Anthony was in the 
forest “headlighting’” for specimens of 
the cat family, he saw a large pair of 
brilliant red eyes glowing from the top 
of a tree, and he fired with the expecta- 
tion of getting an ocelot, or a similar ani- 
mal. Instead of a heavy body crashing 
through the branches there wag a slight 
swish, and in going under the tree he 
found that he had killed a large goat- 
sucker, the biggest of the night-hawk 
family; and while he was disappointed, 
the result of the shot showed that all the 
members of these nocturnal birds possess 
a tapetum. 
On other occasions we found that the 
larger species of the southern Rodents, 
like the agouti and paca, could be easily 
shined at night, and since the northern 
Rodents, with the exception of the rabbit 
(which at best can be doubtfully classi- 
fied as such), do not have shining eyes, it 
is possible that this physical eiement may 
be used as a basis for creating a sub- 
order of Rodents. 
On the upper Chagres we found that 
there was one species of fish which ap- 
parently fed mostly at night, and under 
the light its eyes would glow with the 
same brilliant red possessed by the alli- 
gator, another night feeder. While the 
results in Panama enlarged the number 
of species having reflecting eyes, they 
confirmed more than ever the writer's 
position, that the possession of the tape- 
tum is directly associated with night vis- 
ion, while the brilliancy of such reflec- 
tion, it has been found, corresponds to 
179 
the animal’s need of such a faculty in 
defense or aggression. 
NO PERIODICITY IN HABITS AS IN THE 
NORTH 
The animal I felt a particular interest 
in on this trip was the Central American 
whitetail, a relative of the Virginia deer. 
This species and its geographic repre- 
sentatives are found in all the lower Cana- 
dian provinces, in practically all our 
States and ranges southerly through Mex- 
ico, Central America to the Andes, and 
down into Brazil and Peru. The white- 
tails are now, as in the past, the most 
abundant and widely distributed of all 
the groups of our native deer, and as far 
as northern Mexico are represented by 
several closely related forms, beyond 
which they break into a number of dis- 
tinct species. 
The northerly mating season covers a 
period of about 30 days each fall; the 
bucks commence shedding their horns a 
month or so afterward, while the fawns 
are born in the late spring and within a 
corresponding period of 30 days. Such 
periodic and seasonable habits are un- 
doubtedly caused and controlled by the 
rigorous winters and lack of nourishing 
food during the portion of the year when 
any newly born offspring would suffer or 
perish. Even inthe Gulf States the mating 
and breeding seasons correspond closely 
with those of higher latitudes, due largely 
to the northern origin of the species—with 
the consequent inherited tendencies—and 
also because, even in the most southerly 
States, the colder winds affect many ten- 
der varieties of vegetation. 
After passing the Mexican border, and 
especially from Vera Cruz south, there is 
a considerable enlargement of the breed- 
ing season, since necessity no longer con- 
trols the habits. 
A VARIABLE BREEDING SEASON 
On the Isthmus of Panama, with a 
mean annual temperature of 8o degrees, 
there is only an average difference of five 
degrees between the so-called summer 
and winter months, with the result that 
the rut, the shedding of the horns, and 
the birth of the young are very irregular. 
On the Isthmus the fawns are born dur- 
