XX LIST OF ILLUSTRATIONS. 



PIG. -P^S^ 



177. Outline figure of a human embryo described by Allen Thomson, and 



estimated as about the thirteenth day. (From His) . . .477 



178. Outline figure of a human embryo, lettered by Professor His, S E, 



and estimated as of the thirteenth day. (From His) . . 477 



179. Human embryo lettered by Professor His, S E, and estimated as of 



the thirteenth day. (After His) . 478 



180. Human embryo of about the thirteenth day, from the left side. 



(After V. Spee) . . 479- 



181. The same embryo as in Fig. 180, from the dorsal surface. (After 



V. Spee) . 479 



182. Transverse section across the head end of the human embryo shown 



in Figs. 180 and 181. (After V. Spee) 480 



183. Transverse section across the middle of the body of the human 



embryo shown in Figs. 180 and 181. (After V. Spee) . . 480 



184. Transverse section across the hinder end of the human embryo 



shown in Figs. 180 and 181. (After V. Spee) . . . .480 

 IS.";. Human embryo of about the fourteenth day, from the right side. 



(After Kollmann) 481 



186-388. Diagrammatic longitudinal sections through human embryos, 



representing hypothetical stages intermediate between Eeichert's 



ovum and His' embryos, E or S E. (From His) .... 484 



189. Outline figure of a human embryo lettered by Professor His, Lg, and 



estimated as fifteen days old. (From His) .... 487 



190. Outline figure of a human embryo lettered by Professor His, Soh, 



and estimated as fifteen days old. (From His) .... 487 



191. Outline figure of a human embryo lettered by Professor His, M, and 



estimated as eighteen days old. (From His) . . . 487 



192. Outline figure of a human embryo figured by Allen Thomson, and 



probably about eighteen days old. (From His) . . . 487 



193. Outline figure of a, human embryo lettered by Professor His, B B, 



and estimated as about eighteen days old. (From His) . . 487 



194. Outline figure of a, human embryo lettered by Professor His, Kin, 



and estimated as about twenty days old. (From His) . . 487 



195. Outline figure of a human embryo lettered by Professor His, Lr, 



and estimated as twenty or twehty-oue days old. (From His) . 487 



196. Human embryo at the commencement of the third week. (From 



His, after Coste) 488 



197. Human embryo lettered by Professor His, Lg, and estimated as 



fifteen days old. (After His) 489 



198. Human embryo lettered by Professor His, Lr, and estimated as 



twenty or twenty-one days old. (After His) ... 491 



199. Outline figure of a human embryo figured and described by Coste, 



and estimated as about twenty-three days old. (From His) . 493 



200. Outline figure of a human embryo lettered by Professor His, a, and 



estimated as about twenty-three days old. (From His) . . 493 



201. Outline figure of a human embryo figured and described by AUen 



Thomson, and estimated as about twenty-three days old. (From 

 Hi«) 493 



202. Outline figure of a human embryo lettered by Professor His, B, and 



estimated as twenty-seven days old. (From His) . 493 



