INDEX 



Crossopterygii — (Continued) 



bone of, 108, 130; maxillae 

 and premaxillae of, 107, 130; 

 mouth of, 130; nearest to 

 direct line of ascent, 26; 

 origin of teeth of, 109; tooth 

 structure of, 112, Fig. 18, 

 following, 30; teeth of, 117; 

 possibly possessed a lung, 24; 

 Eusthenopteron (upper Devo- 

 nian), frontispiece; Fig. 12, 

 facing 23; skull of, under side. 

 Fig. 53, 85; Fig. 63, 108; 

 Megalichthys, lower jaw of. 

 Fig. 64, 111; Rhizodopsis, 

 skull of. Fig, 17, 30; Fig. 48, 

 78; Osteolepis, cross section of 

 skull. Fig. 9, facing 20; 

 Polyplocodus, teeth of. Fig. 

 18, following 30; Polypterus, 

 jaw muscles of. Fig. 61, 103; 

 embryo of. Fig. 14, 26 



Cruciform pattern of lower molars, 

 149; Fig. 80, 151 



Crustacea, compound eyes of, 178; 

 mouth-legs of, 6 



Crus helicis, development of the, 

 212 



Cusps, characteristic of the cheek- 

 teeth of mammals, 145 



Cyclostomes, as possible descend- 

 ants of ostracoderms, 98, 186; 

 embryology of the, 186; feed- 

 ing habits of the, 97, 98; 

 lamprey, adult. Fig. 59, 97; 

 lamprey, larval. Fig. 59, 97; 

 mouth-pouches in. Fig. 56, 

 94; "tongue" of, 123; tooth- 

 germs of, (section), Fig. 60, 

 99 



Cynodonts, skulls of. Figs. 48-53, 

 78-85; dentition of, 115, 116; 

 secondary palate of, 119; 

 comparison of molar teeth 

 with those of man, 145; 

 middle ear of, Fig. 112, 217 



Cynognathus, dentition of, Fig. 77, 

 147; middle ear of, Fig. 113, 

 218; jaw muscles of, Fig. 61, 

 103; skull of. Fig. 53, 85 



Darwin, on the origin of mankind, 



65 

 Dawn man, see Eoanthropus daw- 



soni 



Deltatheridium, D. pretrituber- 

 culare, skull and head re- 

 stored. Fig. 29, 50; dentition 

 of. Fig. 77, 147 



Dental formula, of the primates. 

 Fig. 37, 61; of man and 

 anthropoids, 145 



Dentary bone, its development in 

 mammal-like reptiles, 108; 

 evolution in series from fish 

 to man. Fig. 50, 80; contact 

 with squamosal in mammals, 

 87; not dominant in crossopts, 

 108; covered with skin in 

 early amphibia and crossopts, 

 130; crowded out posterior 

 elements, 36; evolution of, 

 87; progressive dominance of, 

 116 

 of armadillo, foetal. Fig. 114, 



221 

 of crossopts, 110, 130 

 of Ictidopsis, Fig, 21, 37 

 of Megalichthys, Fig. 64, 111 

 of Mycterosaurus, 35 

 of Scymnognathus, 36; Fig. 21,37 

 of Thylacinus, 36; Fig. 21, 37 

 of Trimerorhachis, Fig. 64, 111 

 of turtle, embryo. Fig. 64, 111 



Denticles, constitution of shagreen, 

 100; in skin of ostracoderms, 

 117 



Dentition, evolution of human. 

 Fig. 77, 147; Fig. 78, 148; 

 origin of human, 90; reduced 

 to two sets in cynodonts, 116 



Dermal plates (prevomers) of 

 Devonian crossopts, 109 



" Derm-bones," development of, 

 21; of fossil crossopts, 112 



Dermocranium derived from skin, 

 21; its component parts, 83 



Dermo-supraoccipital bone, evolu- 

 tion of. Fig. 49, 79 



Development and growth, Stock- 

 ard's studies of, 172 



Development of the human face. 

 Fig. 86, 165; Fig. 87, 166 



Diadectes (Per mo-Carboniferous), 

 skull of. Fig. 62, 105 



Diademodon, dentition of. Fig. 77, 

 147 



Diaphragm, its origin and func- 

 tion, 41; Sir Arthur Keith on 

 the primate d., 63 



265 



