282 proceedings of the academy of [1884. 



November 18. 

 The President, Dr. Leidy, in the ch:\ir. 

 Thirtj^-seven persons present. 



The deaths of Eli K. Price, C. P. Bayard and J. Edwards 

 Fai'nuBi, members, were announced. 



Urnatella gracilis. — Prof. Leidy remarked that Mr. E. Potts 

 had given to him, in October, 1883, a fragment of a tree-branch on 

 which were many groups of Urnatella. The fragment, tlii'ee inches 

 by one-third of an inch, was obtained in the fore-bay at Fairmount. 

 Around its middle, for about an inch in length, there were thirty 

 separate groups of Urnatella., in nearl}' all consisting each of two 

 stems, of unequal length, and devoid of terminal polyps. The 

 stems diverged and curved downward and were quiescent, but 

 were evidently liAing,as they exhibited slight sensitiveness to dis- 

 turbance. The specimen was placed in an aqnarium, exposed to 

 the north light of a window, and in this position, at the moderate 

 temi)erature of usual living-rooms, was kept during the winter. 

 In March the stems were observed all to have developed polyps 

 at the distal end, in which condition they continue at the present 

 time (April). Most stems are terminated by a single polyp, but 

 a few exhibit a smaller polyp, supported on a cylindrical joint 

 springing from the antepenultimate joint of the stem, including 

 the terminal polyp. The stems are quite irritable and bend in 

 graceful curves from each other on the slightest disturbance. 

 The longer stems even hang their heads in a single spiral turn. 

 The longest stems consist of a dozen joints and measure about the 

 one-eighth of an inch. The shortest stems exhibit one-third the 

 number of joints. The stems appear alternately white and black, 

 the former color corresponding with the thicker portion of the 

 joints, the latter with the constricted portions. Many of the 

 mature joints exhibit traces of the cup-like remains of attach- 

 ment of branches, in most cases on one side only. 



These specimens appear to indicate that, as in the other fresh- 

 water polyzoa, the polyps die on the approach of winter, but the 

 headless stems appear to remain, securely anchored, and ready 

 to reproduce the polyps in the spring. If portions of the stems 

 are destroyed, the remaining joints are capable of reproducing the 

 pol3'ps, commonly from the summit of the terminal joint. 

 Branches usually spring from the last one or two joints, newl}' pro- 

 duced from that which immediately supports the terminal polyp. 

 Specimens also show that heads may start laterally from old or 

 mature joints. Thus the latter appear to serve as the statoblasts 

 of other fresh-water polyzoa, but ordinaril^^ they do not become 

 isolated from one another. As no specimens have been seen 

 with stems consisting of more than a dozen joints, perhaps after 

 reaching this condition, the pol3'ps become detached, to establish 

 new groups. 



The following were ordered to be printed ; — 



