•272 Professor Henslow's Examination 



appearance originate in any optical deception, I could not 

 sufficiently satisfy myself; but if, as I am inclined to think, it 

 does not, the fact must have been hitherto overlooked from the 

 difficulty of detecting the true plane of junction between the 

 contiguous cells, owing to the very great transparency of their 

 membrane. Thus, in Fig. 6, where this epidermis is less mag- 

 nified, the cells appear to be separated from each other by 

 anastomosing veins or canals, whilst in Fig. 7. it is shewn that 

 their true planes of junction run directly along the middle of these 

 canals. I am however quite positive upon another point which 

 has been a subject of dispute among physiologists ; I mean the 

 existence of a delicate homogeneous membrane investing this 

 epidermis. Such a membrane may be distinctly separated by the 

 action of nitric acid, from the epidermis of the corolla, filament, 

 and style. It is faintly marked by parallel longitudinal stria" 

 Fig. 7, (g), and appears to coat over the whole surface of these 

 organs, but whether it is perforated by a fissure opposite each 

 stoma I did ot ascertain. 



Structure of the Filament. Plate xvn. Fig. 8, 9. The cellular 

 tissue of this organ consists of elongated rhomboidal dodecahe- 

 drons, as the elongated hexagons seen in its longitudinal section 

 sufficiently explain (Fig. 9.). A single bundle of tracheae runs up 

 the middle of it, invested by the peculiarly delicate fibrous tissue 

 already noticed. 



Structure of the Anthers. Plate xvn. Fig. 10 — 12. The fibrous 

 cells* composing the inner coat of the anther, appeared to me 

 quite as distinct and perfect in the hybrid as in the parents. 

 Nor did I observe the slightest difference in the formation and 



* See Purkinje " De cellulis antherarum fibrosis, &c. 4to. Vratislavise 1830.' 



