390 DR. A. FARRE ON THE STRUCTURE OF THE CILIOBRACHIATE POLYPI. 
apparently without a knowledge of the discoveries of Edwards and Ehrenberg, was 
described by him as indicating a new form of animal, to which he applied the name 
Polyzoa, to distinguish them from such of the compound animals as partake of the 
nature of Hydra, and he proposed to elevate them to the class of tunicated Mollusca. 
The existence of this type in Flustra has also been since demonstrated by Mr. Lister, 
in his paper on “ Tubular and Cellular Polypi,” communicated to the Royal Society 
in 1834; which contains also much new and valuable information relative to the 
economy of the more simple or hydriform Polypes. 
The descriptions and illustrations of these last-mentioned observers are in various 
degrees confirmatory of each other, and are sufficient to indicate in a general way 
the characters of this more recently discovered form of animal ; but the uses of their 
various organs are often confused and misunderstood, and their minute structure 
certainly not investigated with that degree of accuracy which it deserves, and which 
the present state of science demands. 
It is with the view of supplying these deficiencies that I am induced to lay before 
the Society the result of my own observations upon this very interesting portion of 
the animal kingdom, conceiving that they have been prosecuted to an extent that has 
not hitherto been effected. 
My attention was first particularly directed to the subject in the year 1835, during 
a short visit to the Isle of Sheppy, for the purpose of exploring the various animal 
productions, so abundant on that portion of our coast. During this visit the type of 
structure here referred to came under my notice, and the results of my investigations 
upon it were then so entirely new to me, that I was induced to repeat these visits at 
intervals ; and upon the specimens thus procured, and also upon similar supplies 
obtained from the same place, which I have repeatedly received from my friend 
Mr. Bowerbank, I have been enabled to continue the investigation beyond the limits 
that a mere temporary visit to the coast would have enabled me to do. 
During the early part of these investigations I was but little acquainted with the 
observations that had already been made by others upon the subject. But having 
since been necessarily led to consult these, I find some of my own investigations in 
various degrees confirmed. Those points therefore that are not new I have either 
wholly omitted, or touched upon only to the extent that would be necessary to render 
the subject intelligible. 
The facts that I have thought the most interesting and important to be stated are 
embodied in the descriptions of the various species that furnish the subject matter of 
the present memoir. Two of these species I believe to be entirely new, and I have 
ventured to name them accordingly. 
A few particulars with regard to the method that I have pursued may not be 
without their use, though each specimen will frequently require a different manipu- 
lation. 
A number of glass troughs being at hand (which with the aid of a little cement 
