PRINCIPAL REGIONS OF SPINAL CORD 



81 



cord more flatttened in its cervical region than any other animal 

 in the series here studied. This may be accounted for in part 

 by the extensive innervation required by the greatly developed 

 wing musculature. 



The thoracic region, in general for all the spinal cords, is flat- 

 tened dorso-ventrally. In most cases the flattening is much less 

 than in either the cervical or the lumbar region. The cords of 

 the agouti, lynx, and rhesus monkey are peculiar in that they 



TABLE 5 



Ratio of dor so-ventral to lateral diameter. Table 5 gives the ratios of the dorso-ven- 

 tral to the lateral diameter obtained by dividing the figures in column 2, tables 2, 

 3, and 4 by those in column 1 of the same tables. That is to say, the dorso-ventral 

 diameter is to the lateral diameter as 1 is to the figures here recorded. In each 

 column the animals are arranged in the order of the dorso-ventral flattening of the 

 regions of their spinal cords, those showing the greater dorso-ventral flattening 

 being placed first. The ratio for the lumbar region of the elephant is obtained from 

 diameters given by Kopsch, as quoted from Hardesty. 



CERVICAL 

 1 



Bat 2.23 



Elephant 1.74 



Horse 1.73 



Mouse 1.72 



Ox , 1.69 



Rat 1.55 



Man 1 . 54 



Dog 1.49 



Guinea-pig 1.41 



Rhesus monkey 1 . 35 



Opossum 1.33 



Sheep 1.25 



Spider monkey 1 . 23 



Bear 1.23 



Rabbit 1.21 



Cat 1.19 



Kangaroo 1.17 



Ape 1.16 



Lynx 1.13 



Hog 1.13 



Java monkey 1.11 



Fox 1.05 



Raccoon 1 . 05 



Agouti 0.95 



THORACIC 

 2 



Rhesus monkey ... 1 . 46 



Elephant.. 1.26 



Bat 1.24 



Dog 1.22 



Lynx 1.21 



Mouse 1.19 



Bear 1.18 



Rabbit 1 . 17 



Man 1.16 



Cat 1.16 



Ox 1.13 



Ape 1.12 



Opossum 1 . 09 



Hog 1.08 



Horse 1.08 



Raccoon 1.05 



Kangaroo 1 . 04 



Agouti 1.04 



Sheep 1.04 



Guinea-pig 1.01 



Spider monkey ... 1 . 00 



Java monkey 1 . 00 



Fox 0.98 



Rat 0.90 



LUMBAR 



3 



Ox.... 

 Bat... 

 Rat . . . 

 Horse . 



.1.74 

 .1.71 

 .1.66 

 ,1.65 



Rabbit 1.52 



Elephant 1.52 



Mouse 1 . 46 



Sheep 1.41 



Guinea-pig : 1 . 35 



Dog 1.33 



Rhesus monkey 1 . 29 



Ape 1.27 



Hog 1.26 



Lynx 1.23 



Opossum 1 . 23 



Cat 1.21 



Java monkey 1 . 21 



Kangaroo 1 . 19 



Bear ' 1.17 



Agouti 1.16 



Fox 1.12 



Man 1.11 



Raccoon 1.09 



Spider monkey 1 . 01 



