.LIST OF ILLUSTRATIONS. XVU 



FIG. PAGE 



29. Diagrammatic representation of the Eye of tlie CLicli of about the 



Third Day as seen when -the liead is viewed from underneath as a 

 transparent object ......... 99 



30. D, E, F. Diagrammatic Sections of the Eye of the Chick of about 



the Third Day . 100 



31. Section of the Eye of Chick at the Fourth Day .... 104 



32. Section through the Hind-Brain of a Chick at the end of tlie Third 



Day of Incubation ... . . . . . . j 10 



33. Two Views of the membranous Labyrinth of Columba domer?tica. 



A from the exterior, B from the interior . . . . .112 



34. Transverse Section of the Head of a Fostal Slieep (t6 mm. in 



length) in the region of the Hind-Brain . . . . .11.1 



35. Section of the Head of a Foetal Sheep (20 mm. in length) . .114 



36. Section tlirough'the internal Ear of an Embryonic Siieep (28 mm. 



in length) 116 



37. Head of an Embryo Chick of the Third Day viewed sideways a.s an 



Opaque Object . . . . . . . . . .118 



38. The same Head as shewn in Fig. 37, seen from the Front . 121 

 39 A. Diagram of the Arterial Circulation on the Third Day . .122 

 39 B. Diagram of the Venous Circulation on the Third Day . .124 



40. Section of the Tail-end of an Embryo (Chick) of the Third Day . 125 



41. Section through the Dorsal Region of an Embryo at the commence- 



ment of the Third Day . ' . .... . .126 



42. Diagram of a portion of the Digestive Tract of a Chick upon the 



Fourth Day. ■.".'., 12S 



43. Eour diagrams illustrating the Formation of the Lungs . . .129 



44. Section through the Dorsal Region of an Embryo at the end of 



the Third Day 155 



45. Head of an Embryo Chick of the Third Day (seventy-five hours) 



viewed sideways as a transparent object 137 



46. Embryo at " the end of the Fourth Day seen as a transparent 



objec.t . , 142 



