148 



THE DISSECTION OF PIG EMBRYOS FOR STUDY 



roots, the spinal ganglia are carried ventral to the cord. The body of the embryo 

 also grows faster than the spinal cord, so that the spinal nerves at first directed 

 at right angles to the cord course obliquely caudad in the lumbo-sacral region. 



Sernilunar ganglion n. 5 Ophthalmic ramus n. 5 

 Geniculate gang. n. 7 



Mesencephalon 

 Cerebellum 



Gang. n. 8 



Gang. sup. n. 9 



G. jugulare n. 10 



G. Froriep 



Auricular r. n. 10 



Gang. n. cerv. i 



Gang, petros. n. g 



N. accessorius 



N. hypoglossus 



Gang. cerv. 5-8 



Gang. thor. i 



Lung 



Diaphragm 



Dorsal lobe liver 

 Mesonephros 

 Metanephros 



Cerebrum 



Hypophysis 



N. opticus 



Lobus olfactorius 



'Maxillary ramus n. 5 

 'Mand. ramus n. 5 

 Chorda, tymp. n. 7 



N.facialis (7) 

 Gang, nodosum n. 10 



Lumbar gang. 



Nerve to lower limb 



R. atrium 



R. ventricle 



Ventral lobe liver 



Umbil. cord 



Lower limb 



Sciatic nerve 



FIG. 140. Lateral dissection of a 35 mm. pig embryo to show the nervous system and viscera from the 



right side. X lYi- 



Median Sagittal Dissections (Figs. 141 and 142). Preliminary to the 

 dissection, a cut is made dorsally as near as possible to the median sagittal plane. 

 Beginning caudally at the mid-dorsal line an incision is started which extends in 



