PLATE XVI. 



Halonia regularis. 



Fig. 1 (No. 35) represents a portion of a root, showing the tubercles, having a raised 

 central pimple, and the woody axis in the inside of the root. From the Upper Brooks- 

 bottom seam of Coal, Lancashire. Natural size. 



Fig 2. A transverse section of the root, showing the medulla, woody cylinder, a 

 vascular bundle, portions of the parenchyma, and the outer radiating cylinder. Magnified 

 5 diameters. 



Fig. 3. A longitudinal section of the root, representing the medulla, vascular 

 cylinder, parenchymatous tissue, and outer radiating zone. Magnified 10 diameters. 



Fig. 4. A transverse section of the medulla and woody cylinder. Magnified 10 

 diameters. 



Fig. 5. A transverse section (nearly at right angles) of one of the vascular bundles 

 in the inside of the root. Magnified 40 diameters. 



