PROGRESS OF MICROSCOPICAL SCIENCE. 
201 
those of the sandstone casts, were more prominent than the rest. The 
endotesta was invested by a delicate parenchymatous sarcotesta. All 
these seeds appear to have Cycadean rather than Coniferous affinities. 
One winged seed alone (Polypterospermum), from the uppermost 
coal-measures at Ardwick, resembles a true conifer. In conclusion, 
the author calls attention to the number of yet unknown stems and 
leaves of Phanerogams, which must have belonged to the numerous 
seeds now known to exist in the coal-measures of England, France, 
and North America. 
Multiplication hy Fission in Stentor Miilleri. — Mr. J. D. Cox has an 
interesting paper on this subject in a recent number of the ' American 
Naturalist.' He says : — I had the good fortune, one evening lately, 
to observe the whole process of the division of a large Stentor Miilleri 
into two complete individuals, by fission. The circumstances were 
favourable for pretty carefully noting the phenomena exhibited as 
the change went on, and there were some of them which I have not 
seen narrated, and which have a direct bearing upon the question of 
the organization of this group of infusoria. 
The water was from the Maumee Eiver at Toledo, Ohio, on Lake 
Erie, and contained a good variety of infusoria and of rotifers, which 
had propagated quite rapidly in the glass jar, among some aquatic 
plants carelessly thrown into it. The specimen of Stentor under 
consideration attracted my attention by its size, as it was about four 
hundredths (-04) of an inch in length, the stalk being stretched till it 
appeared about one-half longer than the proportions shown in the 
engraving of Stentor Miilleri in the ' Micrographic Dictionary.' 
Whilst examining other forms in the compressor, I returned to 
this from time to time to enjoy its beauties, and soon noticed that the 
ciliary motion was extending from the disk, at the point of depression 
in its horseshoe shape, down along the body about one-quarter of its 
whole length, and this gradually became more marked. The portion 
of the body immediately under the disk swelled slightly, and the 
general form somewhat resembled the flower of the calla lily. The 
next change noticed was that at the bottom of the slit in the side the 
opening took a rounded form, so that the chain-like motion of the 
cilia looked (as a member of my family expressed it) as if a chain 
were running over a little pulley, and the cilia made a continuous 
fringe around the disk, down the body, and around the circular end 
of the slit. The body now began to show a protuberant swelling 
immediately under the small circular opening at the lower end of the 
ciliated slit, and in a few minutes this enlargement equalled in 
diameter the previous thickness of the body of the Stentor at this 
point, thus doubling its size at the point of greatest expansion. The 
protuberance was distinctly on one side of the body, and appeared as 
an excrescence, the ciliated line running out to its apex. The swelling 
continued to increase, involving gradually the whole circumference 
of the body of the animalcule, the upper side of the protuberance 
assumed a sharper angle to the longitudinal line of the body, be- 
coming more disk-like, while the line of the cilia enlarged so as to 
show an approach to the general form of the original head of the 
