92 PROCEEDINGS OF SOCIETIES, 
MANcHESTER LITERARY AND PuHILosopuican Socorery, 
MICROSCOPICAL AND NATURAL HISTORY SECTIONS. 
October 8th, 1866. 
A. G. Laruam, Esq., President of the Section, in the chair. 
Mr. Hurst read a paper “On the Plants springing up spon- 
taneously on the fresh turning-up of pasture-land at Knutsford, 
Cheshire.” 
“On LEchinus lividus, illustrated by specimens from Round- 
stone,” by Thomas Alcock, M.D.—The author described parti- 
cularly the mechanism of the teeth and jaws of the animal, and 
showed by a dissection of the parts that the statement made both 
by Professor Owen and Professor Rymer Jones that the striated 
surfaces of the jaws are used to comminute the food is incorrect, 
for the whole of these surfaces is occupied by muscle, and is 
altogether outside the pharynx through which the food passes. 
He further showed that the food contained in the alimentary canal 
consists of very coarse pieces of sea-weed and zoophyte, which 
have evidently not been subjected to the action of any triturating 
apparatus. He exhibited mounted specimens of the suckers, and 
also of the sucker-plates cleaned in potash. He said Professor 
Owen quotes Professor Valentin with regard to the Pedicellariz, 
and states that there are three forms of them belonging to Hchinus 
lividus, namely, gemmiform, tridactyle, and ophiocephalous Pedi- 
cellarize :—these were exhibited as mounted specimens, and with 
them a fourth kind, quite distinct from all three, and the most 
remarkable in form; it has long slender jaws like those of a 
crocodile, armed, in this species, with one very long terminal 
tooth and one tooth on each side not far removed from it. He 
remarked that in Echinus sphera all four kinds of Pedicellarize 
are found, and agree in their general character with those of 
Echinus lividus, though they are sufficiently different to be readily 
distinguished, and the fourth kind just mentioned has, besides the 
long terminal tooth, a series on each side of six or seven recurved 
teeth, suggesting the name sauriocephalous as an appropriate 
one for this form. Mounted specimens of the four kinds of 
pedicellarie of Echinus sphera were shown for comparison with 
those of Echinus lividus, together with suckers and sucker-plates, 
and the buccal membrane mounted entire to show the ophio- 
cephalous and gemmiform pedicellarie complete and in their 
natural position. 
“ On the Structure of the Spines of Hehini,”’ by H. A. Hurst, 
Esq.—Notwithstanding the general appreciation by microscopists 
of the spines of Echini, the author has been unable to find any 
satisfactory account of their structure; and he attributed this to 
