174 



STUDY OF PIG EMBRYOS. 



Next in importance comes the sagittal series, but it is desirable that every stu- 

 dent should have a series in the three standard planes at his disposal for study. 

 In the practical laboratory study each student should be required to make a series 

 of accurate camera lucida drawings of carefully selected typical sections; then to 



284 3^ 380 



«^, 



Fig. 112. — Reconstruction of a Pig Embryo of 12.0 mm. with Indications of the Planes of Sec- 



^ TiONs Figured. 



an, Cloacal membrane. Ao, Aorta. Au, Auricle. Aaim, Umbilical artery, a.v. Vertebral artery. l>as. Basilar 



artery, c, Anlage of caecum, car. Internal carotid. frt«, Caudal artery. C.Ex, External carotid artery. 



f.b, Fore-brain. G, Spinal ganglion, g, Gall-bladder, h.b-. Hind-brain. In, Intestine. Li, Liver. 



7n.b, Mid-brain, op, Optic vesicle. Ot, Otocyst. pan. Pancreas. Sp, Spinal cord. St, Stomach. Um, 



Umbilical opening. F<f«, Ventricle of heart. ///, /F, F, Aortic arches. 



185 Transverse section, Fig. 113. 



284 Frontal section. Fig. 126. 



