480 LEON AUGUSTUS HAUSMAN 
very general classification and may be used only in a rough way 
to indicate the general nature of the covering of the dorsum 
and venter, respectively. The covering of the latter consists of 
long, stiff hairs, while the former is beset with long, sharp, rigid 
spines so thickly placed as to cover effectively both the skin 
and their own bases. 
A closer examination of these spines and hairs reveals the fact 
that no definite line of demarcation can be drawn between them. 
From the longest and most robust of the spines of the back to 
the finest of the hairs which can be found on the venter, there 
exist all gradational estates. More will be said later regarding 
this transition in form from the hairs to the spines. It will 
first be necessary, however, to pass in review the various parts 
of the body with reference to the type of hair and spine covering 
which each possesses. 
The dorsum (fig. 48, G) is, as has been said, clothed with a for- 
midable panoply of long, rigid, acuminate spines, closely massed 
together. The largest of these are those which occur in what we 
shall term the ‘hip tufts’ (fig. 48, F). These spines are approxi- 
mately 50 mm. in length and about 4 mm. in diameter in their 
thickest portions. They are of a light yellowish-white hue with 
very dark brown, almost black, tips, the color extending down 
the spine for a distance of about 7 mm. in the case of the longest 
spines (fig. 54). The smaller dorsal spines are like the larger, 
with the exception that their tips are pigmented for a greater 
distance down the shaft, often extending to one-fourth its entire 
length (fig. 56), Because of the closeness with which the larger 
spines are set together, the lower three-fourths of the shafts of 
the smaller spines are hidden. Thus it appears as though the 
dorsum possesses spines of two colors, large yellowish spines and 
smaller black ones. 
The hair of the dorsum is obscured by the spines, and consists 
of two general types: one flattened, straight, and somewhat stiff 
and spinous (fig. 58), and the other smaller, also flattened and 
somewhat stiff, but, in addition, slightly wavy (fig. 59). 
Upon the venter occur three types of hair: a spiny, flattened 
type (fig. 48), a flattened wavy type (fig. 47), and a still finer 
