On the Anatomy and Physiology of some Zoophytes. 385 
great in directing observers in a fruitful path and in exciting 
important researches, among which we may mention those of Va- 
lentm, Vogt, Bergmann, Reichert, Bischoff, Barry, Lebert and 
Henle. In my turn [ shall make known the result of the observa- 
tions which I have made upon so disputed a subject—observations 
which during several years have been many times detailed in the 
course of mstruction which I give m the College of France. 
XLIUI.—Anatomical and Physiological Observations on some 
Zoophytes. By Joun Rerp, M.D., F.R.C.P.E., and Chandos 
Professor of Anatomy and Medicine in the University of St. 
Andrews. 
{ With a Plate. ] 
In the following observations upon the structures and actions of 
some of the Zoophytes obtained from the shore of the bay of 
St. Andrews, I have confined myself to those points which are 
either new, or which appeared deserving of additional illustration. 
In using the terms superior and inferior, upper and lower in re- 
ference to the relutive position of different parts of the polypidom, 
in the descriptive parts of this paper, the polypidom is supposed 
to be in the erect position, so that these terms correspond to an- 
terior and posterior when the polypidom is placed horizontally. 
In using the term anterior surface, 1 mean the surface on which 
the apertures of the polype-cells are placed, so that this corre- 
sponds to the upper surface when the polypidom is laid hori- 
zontally for examination. 
Cellularia reptans. ‘This polype grows im considerable abun- 
dance close upon low-water mark, on the exposed surface of a stra- 
tum of clay-slate and conglomerate, interposed among strata of 
sandstone belonging to the carboniferous series. Growing along 
with it, but in much smaller quantities, are Cellularia scruposa, 
Crisia chelata, C. eburnea, Pedicellina echinata, Vesicularia spi- 
nosa, Valkeria imbricata and Plumularia falcata, none of which 
have I hitherto found adhering to the surrounding strata of 
sandstone. 
The polypidom of this polype possesses some structures which 
as far as J am aware have not yet been described. At the external 
and upper angle of the cell, and posterior to the two spines at- 
tached to this angle (PI. XII. fig. 1 a, fig.2c, a, 6), three of these 
structures are found*. The uppermost of these is a hollow pro- 
cess (fig. 2 6), the superior extremity of which is free, looks out- 
wards and a little forwards, and has an aperture notched on the 
* Part of this process is seen on looking at the anterior surface of the 
polypidom, as is represented in Plate XII. fig, 3b. 
