HOLLAND AND PETERSON: OSTEOLOGY OF THE CHALICOTHEROIDEA. PASSO 
nutrient foramen of considerable size leading upward into the body of the superior 
arch. 
The neural canal of the atlas is narrower behind than in front and is expanded 
internally at the middle on either side. In specimen No. 1604 the transverse 
diameter between the condylar articular surfaces is fifty-three millimeters; the 
transverse diameter between the lateral faces for the axis is forty-three millimeters; 
while the transverse diameter within and midway between the anterior and the 
posterior openings is seventy millimeters. The diagram reproduced in Fig. 22 
represents the contour of the neural canal at its middle as shown by a horizontal 
section. 
MEASUREMENTS OF THE ATLAS.?! 
No. 1604 No. 1728 No. 1726 
(mounted specimen, (medium sized, (immature, sex 
o'), adult? 9), undeterm.) 
mm. mm. mm. 
Createstnransversemdamereieereree nee eae accion 200 146 125 
Greatestaverticalidiame ler anne eee ene ieee eneiane 88 77 55 
Transverse diameter of the neural canal behind................ 43 39 38 
Vertical diameter of the neural canal behind.................-. 57 49 38 
Antero-posterior diameter of the superior arch................. 65 52 36 
Vertical diameter of superior arch at the middle................ 15 9 9 
Antero-posterior diameter of inferior arch...................... 51 40 30 
Vertical diameter of inferior arch at the middle................. 24 21 11 
Vertical diameter of faces for occipital condyles at middle ....... 50 40 37 
Horizontal diameter of faces for occipital condyles at middle..... 50 39 34 
Vertical diameter of faces for the occipital condyles where 
theyaappLoximaLencachwotheGenrrr ar er rier aenean re 28 15 9 
Distance between faces for occipital condyles above............. 33 32 31 
Distance between faces for occipital condyles below............. 11 10 6 
Diameter of face for odontoid process................00000-0e 22 15 12 
Vertical diameter of lateral faces for axis at middle............. 42 37 36 
Horizontal diameter of lateral faces for axis at middle........... 66 51 36 
Distance between outer margins of lateral faces for axis......... 120 95 89 
Vertical diameter of foramen for first spinal nerve.............. 9 5 4 
Horizontal diameter of foramen for first spinal nerve............ 18 12 6 
Distance from condylar articular surface to the bottom of the 
anterior notch of the transverse process..................- 41 29 17 
Distance from the bottom of the anterior notch of the transverse 
process to the anterior end of the vertebrarterial canal...... 35 42 38 
Diameter of the vertebrarterial canal......................... G 8 4 
Length of the vertebrarterial canal.......................-.0. 44 21 10 
1 Numbers in italics indicate approximate measurements. 
