24 Prof. H. Karsten on the Formation, 
the apex, thence more abruptly narrowed, apex briefly and ob- 
tusely truncated ; lateral carinz sharp and smooth, surface faintly 
punctured towards the base, and covered besides with minute 
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 ; 
tibize ringed with ashy ; tarsi with the two basal joints grey. 
6 Coxe 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 lke 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. Karsren. 
[Continued from vol. xiii. p. 485, in which volume the PLATE will be found. | 
§ VIL 
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. 
Tue species of the genus Spirogyra are usually adduced by the 
supporters of Mohl’s 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 
