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PROCEEDINGS OF THE 



[April, 1857. 



one pair corresponding to each joint of the stem. The cells are 

 triangular, or more or less flask-shaped; the aperture being quite 

 narrow. The polyps which are capable of being retracted en- 

 tirely within the cells, when protruded stretch far beyond it, dis- 

 covering an elongate body. 



The prolific capsules appear to be developed on the sides of the 

 stem, between the polyp-cells, and to be usually of a form resem- 

 bling, generally, that seen among Campanularidae ; but in the fol- 

 lowing species I have observed from the same part of the stem 

 the growth of very elongate, narrow, almost tubular vesicles, not 

 much larger at the mouth than at the base, and twisted in partial 

 spiral, like a horn. Whether, as Dalyell thinks is the case in 

 Antennularia, there are more than one kind of vesicle to be found 

 in the same species of this genus, my observations do not enable 

 me yet to decide. 



Distribution. — Seas of Europe, Charleston Harbor and East 

 Indies. 



DYNAMENA CORNICINA nov. spec. 



This very delicate species consists of an unbranched stem, 

 rarely, if ever, equalling half an inch in height. Each joint of the 

 stem, with its two opposite polyp cells, instead of presenting a 

 triangular outline, has the appearance of lateral emargination, 

 from the fact that the aperture of the cells is slightly elongate and 

 tubular and is continued not in the direction of the main axis of 

 the stem, but is bent outward from it. The polyp, when extended, 

 equals, in transverse diameter, the diameter of the cell-mouth, and 

 its whole length somewhat surpasses twice that of the cell. At 

 its free extremity is a circle of about sixteen, rather short and 

 stout, but quite flexible tentacula, surrounding an oral area 

 which, though usually of the rounded hemispherical form, which 

 is generally characteristic of Sertularidae, is capable of being oc- 

 casionally protruded in a somewhat proboscidi form manner. Yet 

 there is no distinct organ of this kind separated from the body by 

 a well-marked constriction, as among Campanularidae. 



This species is found growing on denuded Gorgonia stems. 

 The curved horn-shaped cells have been observed in the begin- 

 ning of March, and in the end of June. They open in a direction 

 at right angles to that of the ordinary sessile cells, and on the two 

 occasions on which they were observed, they bore polyps with 

 tentacula, in one instance, eight to twelve in number. That these 



