IN VEGETABLE BIOLOGY. 



G23 



are frequently placed at the meeting-angles of the cells. They 

 may be composed of small pyramids with blunt apices, or of a 

 greater or less number of flat plates, or of clinorhombic crystals, 

 or of a medley of the above. The masses are sometimes greatly 

 reduced, as is shown at fig. 2, which represents a sphere-mass 

 made up of a clinorhombic crystal capped by two small pyramids. 



Fig. 2. Fig. 3. 



Fig. 2. Small sjihere-crystal, composed of a clinorhombic crystal. 

 Fig. 3. Cellulose skeleton investing a five-sided prism. From a preparation 

 treated with hydrochloric acid. X 600. 



(3) Five- (occasionally six-) sided short prisms with plane 

 faces. These are best studied in sections treated with hydro- 

 chloric acid, which dissolves out the crystal, leaving a delicate 

 skeleton of cellulose (fig. 3). It often happens that the angles 

 of these crystals are not well developed. 



(4) Twin crystals are of frequent occurrence (fig. I), and occa- 

 sionally mulberry-masses (the crystals composing which are 

 exceedingly small) are to be found. 



These crystals are in various ways surrounded and attached 

 to the wall by cellulose. Examples of this attachment are drawn 

 Fig. 4. Fig. 5. Fig. 6. 



Fis. 7. 



Fig. 4. A single cell, showing a shortly pedicellate sphere-crystal, the cellulose 



bands in association with it stretching Borne way across the lumen of 



the cell. X600. 

 Fig. 5. A clinorhombic crystal in a well- developed investment of cellulose 



X 600. And two pyramids, X 600. 

 F«gs. 6, 7, and 8. Cellulose investment of crystals dissolved in hydrochloric 



acid. X 600. 



