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PROCEEDINGS OF THE 



[April, 1857. 



question for investigation. I saw one of those connected with 

 the primary polyp-cell apparently discharging what seemed to 

 be refuse matter. 



The greater polyps have each the form of a hemisphere, at- 

 tached by its plane surface to the pedicle which connnects it with 

 the bottom of the cup. Around the periphery of the hemispheri- 

 cal body is a circle of from twelve to sixteen tentacula serrate 

 with thread-cells, which being more crowded at the extremity 

 formed a sort of terminal pad. The mouth appeared to be a sim- 

 ple opening on the summit of the curved surface, surrounded by 

 a slight fold of the external membrane, in which were implanted 

 at regular intervals from each other a dozen round corpuscles, 

 which probably are thread-cells. 



The polyps did not appear to be capable of stretching far be- 

 yond the opening of the cell. They simply expanded their ten- 

 tacula over its rim, as is done by the polyps of Campanularidse. 



This specimen was taken on the last day of July, and at that 

 season there were no prolific vesicles upon it. 



The arrangement of the secondary cells around the primary 

 ones, in this species, is more like that which obtains in Aglaophe- 

 nia than any which I have seen figured. Indeed I know of no 

 species of Plumularia in which the two lateral secondary polyps, 

 which are never very obvious, have been described as existing at 

 all. Even in Aglaophenia they seem to have been sometimes 

 overlooked, and I can scarcely doubt that they will be observed 

 in some of the European species, if carefully sought after. 



AGLAOPHENIA. Mihi. 

 Syn. Plumularia, (pars) Lamarck. 

 Aglaophenia, (pars) Lamouroux. 



Polypidom, consisting of an unbranched or sparingly branched 

 main stem, with short, lateral pinnae, which bear the polyp-cells. 

 It is either erect or creeping. The erect form has a tortuous and 

 loosely interlacing root-like prolongation, with which it entwines 

 itself around other objects. 



Each group of cells occupies a separate joint of the stern. The 

 great cells are compound, each cell being composed of an anterior 

 and posterior portion, of which the latter bears a projecting tubu- 

 lar process, or secondary cell, and the former the usually dentated 

 opening of the great cell. Just beneath this circle issue from the 

 stem, one on each side of the cell, two tubular processes, or second- 



