228 EXPLANATION OF THE PLATES. 



PLATE IV. 



Fig. 1. Dorsal muscles of a foetal pig three and a half inches 

 long. 



2. The fibre c from the previous figure, after the applica- 



tion of acetic acid. 



3. From the brachial muscles of a foetal pig seven 



inches long. 



4. Primitive muscular fasciculus from the cockchafer. 



5. Muscular fasciculus from a pike. 



6. A portion of the ischiatic nerve of a foetal pig mea- 



suring four inches. 



7. Fasciculus of nervous fibres from the brachial plexus 



of a foetal pig four inches in length. 



8. Single nervous fibres : a, from the nervus trigeminus 



of a foetal pig measuring six inches and a half; b, 

 c, d 3 from the nervus ischiadicus of the same. 



9. Nervous fibre from the vagus of a calf. 



10. Ganglion -globules from the lowest ganglia of the 



sympathetic of a frog. 



11. Capillary vessels in the tail of the tadpole. 



12. Ideal representation of the formation of the capillary 



vessels in the area pellucida of a hen's egg. 



