XVI 



LIST OF ILLUSTRATIONS 



FIGURE PAGE 



343. Left lower deciduous teeth, superior 



aspect, enlarged four times . . . 421 



344. Eruption of permanent first upper 



incisor tooth, natural size .... 422 



345. Eruption of permanent first upper 



incisor tooth and loss of decidu- 

 ous first lower incisor 423 



346. Eruption of permanent second upper 



incisor tooth, permanent first 

 upper incisor in position, perma- 

 nent first and second lower in- 

 cisors pushing out corresponding 

 deciduous teeth 423 



347. Eruption of permanent third lower 



incisor and lower molar teeth, 

 permanent first and second upper 

 and lower incisors in position . . 424 



348. Eruption of permanent third upper 



incisor and first upper premolar 

 teeth, first and second permanent 

 upper incisors in position, in skull 

 one hundred and twenty days after 

 birth 424 



349. Eruption of permanent upper canine 



and third upper premolar teeth, 

 permanent upper molar, decidu- 

 ous canine, and second and third 

 molars in position 425 



350. Eruption of second upper premolar 



tooth, second deciduous molar 

 still in position 425 



351. Eruption of permanent lower molar 



and first lower premolar teeth, 

 deciduous lower molars alone re- 

 maining 425 



352. Eruption of first and second lower 



premolar teeth, deciduous second 

 molar still present 425 



353. Abnormal second upper premolar 



teeth and their alveoli, enlarged 

 one-third 430 



354. Supernumerary left upper premolar 



tooth, natural size. (After Bate- 

 son) 430 



355. Abnormal right second upper pre- 



molar tooth, natural size .... 430 



356. Abnormal second upper premolar 



teeth, natural size 431 



357. Abnormal left second upper pre- 



molar tooth, enlarged four times . 431 



358. Abnormal right second upper pre- 



molar tooth, enlarged four times . 432 



359. Supernumerary upper sectorial 



teeth, natural size. (After Bate- 

 son) 432 



360. Abnormal left upper sectorial tooth, 



natural size 433 



361. Abnormal left upper sectorial tooth, 



enlarged four times 433 



FIGURE PAGE 



362. Abnormal left upper sectorial tooth, 



enlarged four times 434 



363. Abnormal position of second lower 



premolar, natural size 434 



364. Abnormal lower milk molars, en- 



larged 435 



365. Human skull, seen partly in front 



and on the right side. (Leidy) . 436 



366. Human upper and lower permanent 



teeth, exterior view. (Leidy) . . 437 



367. Human upper and lower permanent 



teeth , lateral view. (Leidy) . . 437 



368. Human molar teeth, triturating sur- 



faces. (Leidy) 438 



369. Human temporary teeth of one side. 



(Leidy) 439 



370. Diagrams illustrating the evolution 



of the crowns of the premolar and 

 molar teeth in mammals. (After 

 Cope and Osborn) 444 



371. Eelations of the upper and lower 



cheek teeth, enlarged four times . 455 



372. Variations in the second upper pre- 



molar tooth, enlarged four times . 455 



373. Variations in the second upper pre- 



molar tooth, enlarged four times . 455 



374. Variations in the second upper pre- 



molar tooth, enlarged four times . 455 



375. Variations in the second upper pre- 



molar tooth, enlarged four times . 455 



376. Variations in the second upper pre- 



molar tooth, enlarged four times 455 



377. Variations in the second upper pre- 



molar tooth, enlarged four times . 455 



378. Variations in the second upper pre- 



molar tooth, enlarged four times . 455 



379. Second lower premolar tooth, en- 



larged four times 455 



380. Variations in the second upper pre- 



molar tooth, enlarged four times . 455 



381. Variations in the second upper pre- 



molar tooth, enlarged four times . 455 



382. Upper sectorial tooth, enlarged four 



times 455 



383. Diagram of apposition of upper and 



lower posterior teeth, when upper 

 second premolar has an inner 

 cusp 456 



384. The skull, front view 458 



385. The skull, from above 461 



386. The skull, lower aspect ... .464 



387. The skull, the left side 470 



388. The skull, left side, zygoma and 



lower jaw removed to show orbit 474 



389. The skull, posterior or occipital as- 



pect 478 



390. The skull, cranial cavity from above 480 



391. The skull, side view of cranial and 



nasal cavities . 482 



