1899] A TRILOBITE FROM NEWFOUNDLAND 13 
Mexican and Central American Squirrels. 
In the first volume of the Proc. Washington Acad. (pp. 15-106), Mr. 
E. W. Nelson attempts a revision of the species of squirrels inhabiting 
Mexico and Central America. In these days of “scrappy” papers, it 
is always refreshing to meet with anything of the monograph type; 
and a welcome should therefore be extended to this communication, 
even if we fail to accept all its conclusions. 
The most generally interesting part of the paper deals with the 
degree of development of the fur of these rodents, according to the 
nature of the climate they inhabit. “The effect of climate,” writes the 
author, “on the character of the pelage is so marked, that it is possible 
to tell with considerable certainty whether a species belongs to the 
tropics or to the higher mountains. Tropical species have thin 
pelage, short thin under-fur, and coarse, stiff, or almost bristly dorsal 
hairs; those of the Transition and Boreal zones have thick, soft 
pelage, with long dense under-fur. . . . Species of the hot coasts of 
Central America are characterised by peculiarly coarse, shining, bristly 
dorsal hairs. Seasonal differences in pelage are usually slight, since 
there is no area of heavy snow-fall or long-continued cold weather 
except in the Sierra Madre of Durango and Chihuahua. Individual 
variation, on the other hand, is often excessive, and renders some 
species extremely difficult to describe.” 
This, so far as it goes, is zoology in its highest and best sense. 
With regard to the descriptive portion of the paper, it must suffice to 
say that while the author finds it necessary to split up the genus into 
a number of groups, it is satisfactory that these are regarded in the 
light of sub-genera rather than distinct genera. 
Spinning at Dawn. 
Dr. Emit A. GoELDI, the enthusiastic director of the museum in Para, 
tells an interesting story of an early rising spider—Zpeiroides bahiensis 
Keyserling by name. The spinner was common in his garden, but 
the web defied discovery until Goeldi’s son Walther, a boy of seven, 
sat up to detect the trick. The fact is that the spider makes its web 
in the early hours, and rolls it up and decamps after the sun rises. 
Penelope-like it destroys its web daily, but not without result to man 
as well as to itself, for it catches the minute winged males of the 
destructive Coccidae, of Dorthesia americana in particular. After 
retiring under the shade of a leaf the spider investigates the insects in 
its rolled up net, and spends the hot hours in digesting them. Its 
behaviour reminded Goeldi of a southern bird-catcher hastily gathering 
his roccolo together as the dawn breaks, but with this difference that 
