Neanderthal, the dotted line Spy man No. 1, and the broken line Spy man No. 2, show how closely they coincide, especially in the case of Spy man No. 1, which is scarcely distinguishable from the Neanderthal. The skull of Spy man No. 2, while retaining the general characteristics of the Neanderthal, is more arched and higher in the frontal region. The cephalic index of Spy No. 1 is seventy; that of Spy No. 2, seventy-four to seventy-six.
The immensely developed brow ridges (superciliary crests) are not known in any existing race, nor is the rapidly retreating forehead, except in rare and isolated cases. Both are well-known characters in the Simiidæ. The characters exhibited by the lower jaw are remarkable, and are presented by no existing human race. The angle formed by the anterior face of the mandibular symphysis with the inferior border of the horizontal ramus (that is, the angle between the chin and the lower jaw) is an obtuse angle, while in all existing races it is an acute angle. There is no chin prominence in the Spy men.
The posterior face of the mandibular symphysis (that is, separating the lower jaw at the chin and exposing the separated faces) presents characters approaching an outline intermediate between the anthropoid apes and existing man, as illustrated on the screen by outline drawings of the symphyses of the chimpanzee. Fig. 7.—Skull or the Old Man of Cro-Magnon, Eyzies. (Reindeer epoch. ) Spy No. 1, Spy No. 2, and modern man. By comparing the corresponding parts as represented by the letters this will be evident. Thus the concavity P exists in the chimpanzee and Spy No. 1 and No. 2, but is scarcely discernible in existing man; the prominence G exists in the chimpanzee. Spy No. 1 and No. 2, and is scarcely discernible in existing man. The concavity T has the same relation;
the prominence B, for the insertion of the genioglossal muscles, exists in all; and from this point the outline slopes rapidly forward in existing man and Spy No. 1 and No. 2, while less so and to a less defined termination in the chimpanzee. The upper part of the outline, except that it is more vertical, corresponds more nearly with the chimpanzee, while the lower part corresponds more nearly with existing man.