﻿202 



PROCEEDINGS OF THE 



[April, 1857. 



Distribution. — Southern coast of England and Ireland, Irish 

 channel, Sargasso Sea, and Charleston Harbor. 



AGLAOPHENIA CRISTATA. Mihi. 

 Syn. Plumttlaria cristata, Lamarck. 



Main stems from five to seven inches in height, giving of, on their 

 upper half, two or three pairs of opposite branches, and growing 

 together in a bushy cluster usually upon the top of a worn and de- 

 nuded stem of Gorgonia virgulata, about which their twining roots 

 form a very intricate net-work The polyp-bearing pinnae are found 

 both on the stem itself and on its lateral branches. They are nu- 

 merous, the points of the stems being very short, and a pinna, or 

 branchlet being given off on each side of every joint. One side 

 of the main stem, however, is always roughened by murications, 

 which are the two processes mentioned on every joint of the stem, 

 and which on the lateral pinnae embrace the lower part of the cell- 

 opening. The cells have each about eight or ten (?) prominences 

 around the margin. In form they differ very decidedly from A, 

 pelasgica, being much shorter in proportion to their length. The 

 posterior process also is more nearly central in position, and the 

 two lateral processes are stronger. In addition to this the trans- 

 verse diameter of the cell in j3. pelasgica is so much greater in pro- 

 portion to that of the stem than in the present species, that the cell 

 overhangs the stem when looked at in this position, decidedly more 

 than in present species. The species has, therefore, a thick stem 

 and small cell. The cell also appears to be somewhat more cres- 

 centic in profile, (concave above and convex below,) than in 

 cristata, as figured by Johnston, though they approach that species 

 very closely. If the figures of Johnston, (Brit. Zooph., pi. 23 fig. 

 2, and pi. 94 fig. 16,) be exact, the posterior process also is more 

 conical and pointed, its opening being lateral and anterior, not ter- 

 minal. With regard to the polyps and fleshy parts of the stem, I 

 have not seen them but in their dead and contracted condition But 

 it may be seen, even then, that a distinct prolongation of the fleshy 

 core of the stem is carried up from the posterior portion of the pol 

 yp's base into the conical process of the cell, which represents the 

 posterior secondary cell, and that each of the anterior lateral pro- 

 cesses, or secondary cells, has also such a prolongation. 



The reproductive capsules have a very pod-like appearance, but 

 appear rather more pointed behind than those of A. cristata, figured 

 by Johnston, and increasing gradually in width towards the end of 



