AR HISTORY OF ERITISH ZOOPHYTES. 
had the progress of its growth stopped by some impending 
rock or other accident, part of its upper branches appearing 
as if cut off in a horizontal direction. This, we observe, 
has diverted the course of the animals back the way they 
came, so that we find many of the lately-formed cells covered 
over and confused with an irregular appearance of the cal- 
careous matter. This we can perceive, as far as we can 
trace the animals back in their retreat ; and upon taking off 
the calcareous matter, we find that the horny substance, 
which they had deposited since their return, had filled up 
most of the vacant places in that part of the reticulation.” 
Genus XX. PRIMNOA, Lamour. 
Gen. Char. Polypidom plant-like, irregularly branched; the 
axis horny, becoming very hard, continuous; polype-cells pro- 
truded far beyond the crust, subpedunculated and moveable, 
squamous ; the aperture furnished with eight smaller testaceous 
scales.—Johuston. 
1. Primnoa LEpADIFERA, Professor Jameson. 
Hab. Coasts of Aberdeenshire and Shetland, Jameson. 
“The axis, when young, is corneous, but in the older 
branches it is ike bone. The flesh is covered with minute 
