436 Mr. A. Henfrey on the Progress of Physiological Botany : 
Mr. Smith’s ‘^folded membrane,^ polype-skinj^ &c. are in my 
opinion purely imaginary. If the tubular cavities disposed with 
so much regularity on the inner surface of the fossils to which I 
restricted the term Ventriculites were not cells inhabited by 
polypes, then I affirm that we have, at present, no evidence that 
any of these zoophytes were polypiferous ; and I readily admit 
that this may still be regarded as an open question. The only 
unequivocal instance I have seen of the soft parts of a polype 
from the chalk strata, is one in flint discovered by the Rev. J. 
B. Reade, and figured in the 6th edit, of my ^Wonders of Geo- 
logy,’ p. 304 : but there is no proof that this polype belonged to 
a Ventriculite. 
How far it may be deemed expedient to admit of the applica- 
tion of the term cephalic membrane ” to the margin of a cup- 
shaped zoophyte, or to group together under the name of Ventri- 
culidce the incongruous assemblage of fossil zoophytes thus classed 
by Mr. Smith, I leave for competent naturalists to determine. 
To those geologists who like me aspire only to a general 
knowledge of the organic remains found in the respective strata, 
I believe that the accurate and simple exposition of the form and 
structure of the Ventriculites, given in my works, long before 
Mr. Smith commenced his arduous labours, will be found alike 
true to nature and perfectly intelligible : the sublime transcen- 
dentalisms in the communications to which the above remarks 
refer, are far beyond the comprehension of such humble ob- 
servers as. Gentlemen, your very faithful servant, 
Gideon Algernon Mantell. 
Chester Square, Pimlico, May 5, 184S. 
XLVI. — Reports on the Progress of Physiological Botany. No. 4. 
By Arthur Henfrey, F.L.S. &c. 
On the Multiplication of Vegetable Cells by Division. 
On the 22nd of November 1847, Prof. Mitscherlich read before 
‘■he Royal Academy of Berlin, a portion of an essay on the De- 
velopment and Composition of the Confervse. This has been 
published in the monthly report of the Academy*, and is so in- 
structive that it deserves a somewhat detailed report here. 
Prof. Mitscherlich selected the Confervfe on account of the 
simplicity of their structure and the rapidity of their develop- 
ment, and C. glomerata is the species which he found best 
adapted for the observations, as the cells are very distinct from 
each other, and develope well beneath the microscope. Moreover 
* Monatsbericht der Kbnigl. Preii's. Acad. Nov. 1S47. 
