REPORT ON THE ANTIPATHARIA. 115 



surface of the primary branches a number of elongate branches arise which are directed 

 upwards, taking an almost vertical direction. These constitute the most important 

 branches of the corallum, and may be 10 to 18 cm. in length. They usually become 

 considerably thickened some distance above their origin, and bear a further series of 

 branchlets, without definite arrangement, which may be 0'5 to 1*5 cm. apart, and 3 to 4 cm. 

 long. In addition to these, forming the framework so to speak of the colony, the 

 stem, branches, and branchlets, all bear a number of lateral pinnules which are usually 

 alternate, but the arrangement is often irregular. An enormous development of certain 

 of these pinnules gives rise to the secondary branches and branchlets. They are usually 

 from 0'5 to 1 cm. long, and about 0'2 cm. apart, but near the apex of the corallum certain 

 pinnules are much elongated and bipinnate, or more rarely tripinnate. Fusions are 

 frequent in all parts of the corallum. 



The polyps are small and rounded, showing a tendency to become elongated in the 

 direction of growth, as is usual in this genus. The tentacles are short rounded lobes 

 arranged in a ring around the oral disc, or in the more elongate individuals the tentacles 

 are more nearly arranged in two rows at each end of the long axis of the stomodaeum.. 

 The mouth is situated in the centre of an elevated and rounded oral disc, as large as 

 one of the tentacles. On the larger branches the polyps are frequently distributed in 

 two alternate rows, one on each side of the median line on the anterior surface. They 

 also extend to the posterior surface, but are not so numerous there nor arranged with 

 such regularity. On the branchlets and pinnules the polyps are arranged in a single 

 row along the anterior aspect of the corallum. The various polyps on a pinnule are 

 closely crowded, particularly in the younger portions of the colony. There are usually 

 about seven to a centimetre on the pinnules. 



The spines are short, conical, but somewhat compressed, and are generally bent slightly 

 upwards, and have moderately sharp points. They are arranged in steep spirals from 

 left to right, and also in longitudinal rows. Four rows may be counted from one aspect 

 of a pinnule, the members of a row being about two lengths apart. It will be seen by 

 a reference to PI. I. fig. 3, that the members of a spiral are placed at regular intervals one 

 above another, so that, of the four series figured, the right hand row is inserted at a point 

 on the axis slightly above that on the left hand. In Antipathella assimilis (cf. PI. I. 

 fig. 6) this is not the case. This species is readily distinguished from other members of 

 the genus, on account of the fact that its branches and branchlets form long, narrow, and 

 slender pinnate fronds, rarely more than 2 cm. across the pinnse. Antipathella speciosa 

 comes nearest to it in this respect, but in the species under consideration the whole 

 corallum is relatively long and narrow, the growth is not so regular, and the pinnules of 

 neighbouring branchlets dd not appear to be so firmly fused together into a reticulum. 



Habitat— Station 308 ; January 5, 1876; kit, 50° 8' 30" S, long. 74° 41' 0" W.; Strait 

 of Magellan ; depth, 175 fathoms; bottom, blue mud. 



