300 MR. H. N. MOSELEY ON DEEP-SEA ACTINIARIA 



with a rounded terminal knob, of several sizes, disposed in regular series at the margin of 

 the disk and in two circlets on its surface. 



Copallimorphus profundps, n. sp. (Plate XLV. figs. 7, 8, & 8 a, 8 b.) 



The animal is in form a short cylinder, with flat upper surface or disk, and is rounded 

 below, where the base takes the form of an excavation, its margins being turned inwards. 

 Attached to the centre of the disk, but occupying not nearly its whole area, was, in the 

 single specimen obtained, a small nodule of peroxide of manganese, of which many were 

 brought up by the trawl. The wall of the body of the Actinia is firm and rigid, and the 

 animal is unable to contract so as to shut in the disk and tentacles. 60 tentacles are 

 present, of which 48 are attached to the margin of the disk, and 12 spring from its 

 surface. The marginal tentacles are of three sizes — 24 being very small, 12 much larger, 

 and 12 intermediate in dimensions. The disk, which has a diameter of about 4 centims., 

 shows a series of radially disposed rounded ridges, corresponding to the summits of the 

 intermesenterial chambers. Of those corresponding to the 12 larger tentacles, 6 are 

 broader than the others, and terminate towards the mouth in broader ends ; these may 

 be considered as primary. A pair of them coincide in direction with the long axis of the 

 elongate mouth. These primary rays of the disk bear each a tentacle at a distance from 

 the margin of the disk of about one third their length. The 6 secondary rays bear 

 smaller tentacles, which are placed much nearer to the margin of the disk. The tentacles 

 are elongate conical, with a small knob at their extremities. The mouth is of an elongate 

 oval form, and is sunk in a slight eminence in the centre of the disk. The animal is 

 covered with a hyaline transparent integument, through which the ochre-yellow coloured 

 inner tunics and viscera show themselves. The ovaries are especially conspicuous, 

 being of a dark ochre-yellow, of which colour also is the mouth. The base is of a dark 

 brown. 



The animal has three kinds of nematocysts or thread-cells. One of these is exactly of 

 the same structure as figured by Mobius as occurring in Gary ophy Ilia Smithii*, being 

 extremely large and of an elongate cylindrical form, with narrowed ends. These cells in 

 the present species are remarkable for their great size, being apparently the largest 

 nematocysts known. They measure about - 18 millim. in length, whereas the cells of 

 Caryophyllia Smithii measure only "102 to '071 millim. They are thus specially favour- 

 able objects for examination, and I clearly saw in them tbe peculiar triple invagination of 

 the wide first part of the thread figured by Mobius ; and I also saw the various stages of 

 development of the cells exactly as figured by him. 



The second kind of nematocysts is of nearly the same form as that just described, but 

 a little shorter. It contains a thread which is of uniform dimension, and beset through- 

 out its length with short spines : the thread is simply coiled in a somewhat irregular spiral 

 within the cell. These two kinds of thread-cells occur together in the tentacles of the 

 animal. The third form of nematocysts is shown (figs. 8 a, 8 b) as seen in the expanded and 



* Mobius, " TTeber den Bait, den Hechanismus und die Entwicklung der Nesselkapseln," Abb., nat. Yer. Hamburg, 

 1866. (Cited by Allman, figures copied by Dana.) 



