222 
MR. J. S. BOWERBANK ON THE ORGANIC TISSUES IN THE 
combined with the glutinous animal-looking membrane, without even the slightest 
appearance of reticulated structures, strongly impresses the feeling upon the mind 
that this disputed genus is in truth animal and not vegetable, as we have been led to 
believe up to the present period. 
An examination of our British species, Nullipara calcarea, assists in the confirma- 
tion of the animal view of the subject, as in this we find the cellular structure in a 
much less perfect and regular condition than in the Australian specimens, while the 
vascular tissue, with csecoid appendages, and the membrane, are almost identical with 
those of the Australian Nullipora. 
The animal matter obtained from an undescribed species of Agaricia, nearly allied 
to Agaricia ampliata , exhibited a form of tissue that I have not observed in any other 
coral. The membranous structure and the minute vessels with csecoid appendages 
presented the usual characters, but the latter were not so abundant as in many of the 
specimens I have examined. The remarkable feature is the presence of numerous 
elongated vesicles, which are coated with a fine fibrous tissue regularly disposed in 
diagonal or waved lines across them, as represented in Plate XVII. fig. 8. Some of 
these organs have one or more angles in a longitudinal direction, extending from the 
base to the apex of the vesicle, while others have the appearance of being cylindrical 
sacs. They appear to be attached to the membrane throughout their whole length, 
as neither of their extremities is projected from the plane of the surrounding tissues. 
But from the different aspect of the two extremities, it is evident that they have the ; 
origin from the end and not the side of the vesicle, one termination generally being 
ill-defined and appearing to merge in the surrounding membrane, while the opposite 
one is distinctly visible. The fibrous threads of the vesicle do not pass from the one 
to the other, nor do they appear to originate in the membrane upon which the organ 
reposes. 
These curious fibro-vesicular bodies resemble, in a striking manner, the fibro-cel- 
lular tissue which forms the parenchyma in the leaf of Pleurothallis racemosa. 
I could not detect a cytoblast at either of their terminations, but a few of these 
organs were dispersed upon the membrane. The vessels with csecoid appendages 
frequently passed over them, but in no determinate direction, and I could not detect 
any communication existing between them. The average size of the vesicles mea- 
sured 4 ^-q of an inch long, by ^ qo °f an inch in diameter. 
The results of the examination of the various species of Corallidse which have fur- 
nished the subjects of this paper, are such as we might have expected after a careful 
perusal of the valuable papers of Mr. Lister and Dr. Arthur Farre, published in 
the Philosophical Transactions, 1834 and 1837. In the former, the author has dis- 
played in an admirable manner the circulation of the fluids in the Tubularise and the 
Sertularise ; while the latter, with an equal degree of talent, has rendered us familiar 
with the muscular organization and digestive processes of the ciliobrachiate polypi. 
From these researches it is but natural we should infer that an equal extent of organ- 
