EXPLANATION OF THE PLATES. 
WuHere no other measurement is given, the figure re- 
presents the object magnified about 450 diameters, linear 
measurement. 
PLATE I. 
Fig. 1. Parenchymatous cellular tissue, with cell-nuclei from 
an onion, magnified 290 times. 
2, Matrix of the pollen of Rhipsalis salicornoides. 
3. Do. do. 
I am indebted to the kindness of Dr. Schleiden for the last. two delineations. 
4, Cells from the chorda dorsalis of Cyprinus erythroph- 
thalmus. 
5. Cartilage from the point of a branchial ray, from the 
same. 
6. Cartilage from the middle of a branchial ray, from the 
same. 
7. Cartilage from the root of a branchial ray, from the 
same. 
8. Branchial cartilage from the larva of Rana esculenta. 
9. Cranial cartilage (ethmoid bone) from the larva of 
Pelobates fuscus. 
10. Cells from the crystalline lens of a fetal pig four 
inches long. 
11. An isolated nucleus of the cells of the crystalline lens. 
12. Cells from the crystalline lens of the same feetus, ex- 
hibiting their prolongation into the fibres of the lens. 
13. Fibres from the innermost layers of the lens of a pike. 
14, Cell from the epidermis of a species of grass. 
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