REPORT ON THE ANTIPATHARIA. 159 



Family Dendrobk. achiid^e, Brook. 



Genus Dendrobrachia, n. gen. 



The sclerenchyrna ultimately consists of a rounded spinose axis, but is never hollow 

 and tubular as in the Antipathidse. Towards the apex of a branch it consists of five to 

 seven plate-like portions radiating from a short central rod. The free margin of each 

 plate is dentate. The angle between adjoining plates gradually becomes filled up by a 

 deposition of new layers of sclerenchyrna, until in transverse section the outline is 

 almost circular (cf. PI. X. figs. 6, 7, and 8). 



The polyps are usually remote, and often arranged in subopposite pairs, the base of 

 each polyp extending over half the axis. The polyps do not stand out at right angles to 

 the axis as in Antipathidae, but form an acute angle with it. 



The tentacles, the number of which is uncertain, are pinnate, having a central stem and 

 lateral relatively elongate branches. 



Owing to the imperfect preservation of the type specimen, a satisfactory examination 

 of the structure of the polyps has been found impossible. 



Dendrobrachia fallax, n. sp. (PL X. figs. 1-8). 



The two specimens of this interesting species are about 24 cm. high, but the basal 

 portions of the corallum are not preserved. The stem is nearly round below, has a 

 diameter of 3 mm., and is distinctly tapering. It has an irregular course, gives off a 

 number of branches at irregular intervals, rarely opposite. These again bear smaller 

 lateral and subalternate branchlets at variable intervals, rarely under one centimetre 

 apart on the same side, but in several places the branchlets are subopposite. The 

 ultimate branchlets are from 1 to 5 cm. long. The whole growth is lax and paniculate, and 

 the upper portion of the corallum is quite flaccid. Figs. 6, 7, and 8 on PL X. represent 

 transverse sections of the sclerenchyrna at three different points of a branch. Fig. 6 

 is taken from a section near the apex, fig. 7 near the middle, and fig. 8 from near the 

 base of the branch. 



The sclerenchyrna is deposited in thin lamella? as in other Antipatharia, but there is 

 no central lumen around which the horny layers are secreted. The longitudinal ridges 

 (PL X. fig. 5) have a dentate or spinose margin, but the spines show the greatest 

 irregularity both as regards size and shape. As the intervals between the ridges come 

 to be filled up with sclerenchyrna new rows of spines are formed, until ultimately it 

 would be impossible to distinguish the sclerobasic axis externally from that of Anti- 

 pathidse. In the older portions of the axis the original outline of the radiating plates 

 appears to be lost, but the centre is occupied by an irregular mass of less dense tissue. 



