ABBREVIATIONS. 



(For the meaning of letters a, b, c, d, e, f, in Figures 24-26, see the explanation 

 of those Figures.) 



Ganglion nodosum. 

 Spinal ganglion. 

 Liver. 

 Intestine. 

 Lateral plate. 

 Medullary plate. 

 Mesodermal plate. 

 Peritoneal layer. 

 Protovertebral plate. 

 Somatic layer. 

 Splanchnic layer. 

 Median. 



Basement membrane. 

 Mesoderm. 

 Mesenchyme. 

 Myotome. 

 Nervus lateralis. 

 Chorda dorsalis. 

 Nephrostome. 



^"- 1st, 2d, and 3d pronephric 

 nephrostome, respectively. 

 Peritoneum. 

 Protovertebra. 

 Aortic root. 



Root of the vagus nerve. 

 Sub-notochordal rod. 

 Blood sinus. 

 Somites I., II., etc. 

 Somatopleure. 

 Yolk spherules. 

 Splanchnopleure. 

 . " ' I"- Ist, 2d, and 3d nephro- 

 stomal tubules respectively. 

 Pronephric tubule. 

 Collecting trunk. 

 Common trunk. 

 Blood-vessel. 

 Posterior cardinal vein. 

 Jugular vein. 



