48 JOURNAL OF THE [April, 



the one-eighth of an inch in length ; the shortest stems have one- 

 third the number of joints." From the construction of the stems 

 he further argues : " As in the other fresh-water polyzoa, the 

 polyps die on the approach of winter, but the headless stems ap- 

 pear to remain securely anchored and ready to reproduce the 

 polyps in the spring." 



From my short acquaintance with the new form, I am not at 

 present able to confirm or reject Leidy's theory; but he was a very 

 careful observer, and his recent death was a great loss to science. 



In U. Walkerii the tentacula are from eight to ten in number, 

 and unusually short and stumpy, with thirty or forty cilia on each 

 side. There is an upward circulation — shown in the left of the 

 figure — a crushing apparatus in the oesophagus, whilst the gizzard 

 performs its functions with a quick revolving motion. 



OCTOCELLA LiBERTAS sp. n. (PI. 29, Fig. 4). 



This beautiful little polyzoon I have named Octocella from its 

 possession of eight tentacles, and libertas in recognition of its 

 being found in the shadow of the Statue of Liberty. 



The process known as " introversion " is remarkable in this 

 form, whilst it is also a fine example of ciliary action. It is, 

 when extended, very clear, and is provided with a crushing ap- 

 paratus in the oesophagus, by which the food is prepared for the 

 action of the gizzard beneath. But the structure and mode of 

 reproduction in the Polyzoa have been so frequently and so fully 

 described by able writers that it would be presumptuous in me 

 to enter the lists, unless our small friend should manifest some 

 undescribed peculiarities. 



CORDYLOPHORA CORONATA sp. n. (PI. 29, Fig. 5). 



This member of the group Hydroida must at once take rank as 

 one of the most attractive forms I have beheld in an experience of 

 thirty-five years. As it seems hardy, it is a very valuable addition 

 to our "exhibition objects." I have now in my aquaria some of 

 my original gathering, made more than two months ago. 



When first found, as I did not then happen to be one of the 

 select few who have been favored with a sight of C. laciistris, it 

 was taken for that form ; but on hunting it up in the Philosophical 

 Transactions, 1853, I found that, whatever it was, it was not that, 



