50 JOURNAL OF THE [April, 



As C. lacustris — according to Dr. Stokes — has only been found 

 three times before in this country, twice by the late Prof. Leidy 

 and once by Mr. Carter of Johns Hopkins University ; as Dr. 

 Allman's paper is the only standard authority upon it, and almost 

 as rare as is the animal itself ; and believing it will be fully 

 appreciated by microscopists generally, and at the same time 

 afford a convenient opportunity for comparison with the new 

 form, the authorities of the Society have kindly consented to re- 

 produce the plates of Dr. Allman's paper, as read before the 

 Royal Society, and published in Phil. Travis, for 1853. 



The only additional remark I have to make is on the difference 

 between my illustration of the perfect animal, and Dr. Allman's. 

 My drawing is an almost exact reproduction — making some 

 allowance for perspective — of the position of its twelve tentacula 

 during the fifteen days I had it under observation. As it lived so 

 long, I was indulging the hope that it might bud and multiply ; 

 but when it did collapse, in a few hours there was no trace of its 

 existence left behind. Never did I so sincerely mourn the loss of 

 a specimen, and although I spent many, many hours in searching, 

 I could not find another. 



Note. — Since the reading of this paper I have met an article 

 by the Rev. Thomas Hincks, B.A., published in the Popular 

 Science Review for 1870, describing a polyzoon named Valkeria 

 pustulosa, which in some respects very closely resembles Octocella 

 libertas; but the woodcut is very indistinct, whilst there is no 

 mention made of a tube. If Mr. Hincks be living, perhaps he 

 may be able to throw some light on the subject. 



