﻿April, 1857.] 



ELLIOTT SOCIETY. 



201 



ary cells, like that which characterises the posterior portion of the 

 cell. These two processes embrace the anterior portion of the 

 great cell. The end of the main stem does not terminate in a 

 point, but seems somewhat expanded, as if forming there a calicle 

 for a terminal polyp. The appearance of a series of openings or 

 pores in the main stem, like that described in P. myriophyllum, was 

 observed in the species to be described, but the pores appear fewer 

 and larger. 



The polyp, according to Johnston, has ten tentacula, and a pro- 

 boscidi from mouth. 



The reproductive capsules are, like the cells, also compound. 

 They occupy each the greater portion of one of the pinnae, and are 

 terminal. They appear to be the result of a metamorphosis of the 

 polyps by which the cells are fused together, the polyps remaining 

 distinct. 



I take the P. cristata as the nucleus of this group. The P. 

 plumatella is probably also referable to it, but we know nothing 

 of its reproductive capsules. P. myriophyllum is equally uncer- 

 tain The species found by Dr. Pickering, of the Wilkes' expe- 

 dition, upon Gulf-weed, and figured in Dana's Zoophytes, p. 23, 

 fig. 7 is undoubtedly a member of the same group, and a well 

 marked and distinct species. I have some good specimens of it 

 in alchohol, which 1 owe to Dr. Edmund Ravenel, to whom I have 

 had to offer thanks on a previous occasion for similar favors. These 

 specimens are attached to Gulf-weed, (Sargassum pacciferum) and 

 were taken in the Atlantic by a homeward bound vessel. I think it 

 in all probability identical with the Plumularia pelasgica of La- 

 marck, Sertularia pelasgicaTSosc, Dynamena pelasgica, de Blainville. 



It is characterised by cells quite long in proportion to their 

 breadth — the posterior process is far behind; the anterior lateral 

 processes, are rather weak and slender. The main stem is re- 

 cumbent and creeping, giving off at intervals plume-like branches, 

 so much like those of the ordinary true Plumularia, that it would 

 readily be mistaken at first sight. On my specimens I have found 

 no reproductive capsules. This important portion of the commu- 

 nity, however, is represented in Dana's wood cut, /. c. It is turned 

 downwards, thus depending from the stem; is this its natural 

 position ? 



This species is not improbably an occasional visitant of our 

 waters, but I have never encountered it on the Gulf-weed thrown 

 on our beaches. 

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