TRANSACTIONS. 
On the Self-division of Micrasterias denticulata. 
By Mr. Lobb. 
(Head October lOtli, 1860.) 
In the month of April last^ Dr. Millar^ Mr. Mummery, 
and myself, went out collectmg in Epping Forest, near High 
Beech, where the Doctor has a residence ; and he being well 
acquainted with the localities, we soon filled our bottles with 
Volvox globator, Volvox aureus, Actinophrys sol and viridis, 
Difflugia, Floscularia, Diatomacese, Desmidiacea3, &c. And 
I may here take the opportunity of saying, that I know of 
no place so prolific in microscopic gatherings as Epping 
Forest, which exceeds even the noted bog at Fisher^s Castle, 
Tunbridge Wells. On examining, the next morning, the 
Desmidiacese, I was favoured with a beautiful view, from com- 
mencement to termination, of the self-division of Micras- 
terias denticulata, occupying altogether three hours and a 
half ; the result was to make me feel that Mr. Ealfs is wrong 
in the figure he gives of the same in his highly valuable work 
On the British Desmidiaceae (fig. 1, pi. 7). So humble an 
individual as myself may well pause on differing from so high 
an authority, but in this instance I am compelled to do so, 
and am happy to say that I am not alone in so doing, Mr. 
Tomkins and Dr. Millar having both witnessed the same, 
and both of them perfectly agree with me. Mr. Tomkins 
saw it first, myself next, and lastly Dr. Millar. 
The self-division commences by the exudation of a small, 
perfectly hyaline, membranaceous globule from each half- 
frustule; very soon a small portion of granular endochrome is 
seen issuing forth into the globules from the original half- 
frustules. (See PI. I, fig. 1.) 
The next stage exhibits the globules dividing into three lobes, 
the endochrome increasing in quantity, sometimes gradually 
extending itself as in fig. 2, and sometimes entering, as it 
were, in two streams from the thickened sides of the end 
lobes of the parent half-frustules, as in fig. 3. 
In the next stage the three lobes divide into five; the 
end lobe remaining unaltered in figure, and only increased 
in size. (See fig. 4.) 
VOL. I, NEW SER. a 
