24 Prof. H. Karsten on the Formation, 



the apex, thence more abruptly narrowed, apex briefly and ob- 

 tusely truncated; lateral carinas sharp and smooth, surface famtly 

 punctured towards the base, and covered besides with mniute 

 setiferous punctures, clothed with tawny pile, much spotted and 

 patched with black, the apical region on each elytron being 

 occupied by a large clear black spot margined with ashy. Body 

 beneath ashy tawny. Legs blackish, with scant tawny clothing ; 

 tibiffi ringed with ashy ; tarsi with the two basal joints grey. 



c? Coxffi and breast densely hairy, as also (in well-developed 

 examples) the middle of the abdomen. Terminal abdominal 

 segment with ventral plate sharply notched, dorsal moderately 

 so. Fore and middle tarsi dilated and fringed with hairs. 



Also found on the banks of the Cupari. M. Bar has since 

 met with it in the interior of French Guiana. The species, 

 although having an elongated form of body like the Colobothea, 

 does not offer the peculiar facies of that genus, owing to the 

 different shape of the apex of the elytra. 

 [To be continued.] 



III. — Histological Researches on the Formation, Development, 

 and Structure of the Vegetable Cell. By Prof. H. Karsten. 



[Continued from vol. xiii. p. 485, in which volume the Plate will be found.] 



§ VIII. 



Conditions of growth of Spirogyra. — Endogenous cell-tissue of the joint- 

 cells, consisting of chlorophyll-vesicles and colourless secretion-cells. — 

 Celluline present in the latter as well as in the mother cell, but con- 

 sumed in the course of vegetation. 



The species of the genus Spirogyra are usually adduced by the 

 supporters of MohFs theory of cell-development, together with 

 Cladophora glomerata, as indubitable examples of cell-multiplica- 

 tion by constriction. 



The difficulties attending the cultivation of these plants, to- 

 gether with the great delicacy and ready destructibility of the 

 membranes of their endogenous cells, are without doubt the rea- 

 son that hitherto, notwithstanding the very simple and regular 

 structure of the plants, the presence of these cells has not been 

 recognized ; and still less has a complete knowledge of their 

 course of development and of the production thereby of the 

 septal walls been attained, as these cells, on account of the 

 great sensibility of the plant to slight changes in the influences 

 of external agents, can usually be observed directly in their 

 growth only for short periods. 



Moreover the Spirogyra, like many, if not all, of their allies, 

 are apparently incapable of assimilating pure inorganic matters 



