CURVE or SPEE IN MAMMALS 
185 
center of the circle lying in the cyhnder-surface or the "center angle," 
and the curvatures of the curves of Spee were compared with each 
other by comparing the lengths of the radii of the circles to which 
they belonged. When the data are arranged according to the di- 
minishing values of the "center angle," the relations shown in table 
19 are brought out. 
From the data in table 19 it is clear that there is no general relation 
between the value of the "center angle" of the curve of Spee and the 
TABLE 19 
Values for the ''center angle" in various species. Arranged according to the diminishing 
values for the "center angle" 
NAME OF SPECIES 
Rhinoceros 
Simia satyrus 
Porcus babyrussa 
Man 
Didelphys marsupialis . . 
Rangifer tarandus 
Camelus bactrianus .... 
Dicotyles sp 
Fiber zibethicus 
Lama huanacho 
Hylobates miilleri 
Macacus cynomolgus. . . . 
Nasalis larvatus 
Semnopithecus femoralis 
Macacus nemestrinus . . . 
zoological order to which a given species belongs. For example, in 
Simia satyrus (orang utan) the "center angle" amounts to 35.6 degrees; 
in Hylobates miilleri it is as small as 22.9 degrees. Both of these are 
primates. On the other hand, in the Rhinoceros, a perissodactyl, 
the "center angle" amounts to 38.4 degrees, and in Rangifer tarandus, 
an artiodactyl, it is 25.5 degrees. 
Similarly, we do not find any close relation between the length of 
the radius of the curve of Spee and the order of mammals to which 
the species belongs. This fact is shown in table 20, in which the data 
are arranged according to the diminishing length of the radius. 
VALUE or 
"center angle" 
degrets 
38.4 
35.6 
31.3 
28.6 
27.7 
25.5 
25.3 
23.9 
23.9 
23.4 
22.9 
21.8 
19.8 
18.8 
16.3 
