REPORT ON THE ANTIPATHARIA. 121 



The spines are small, numerous, and triangular, with a sharp apex. The base is broad, 

 often equal to the length of the spine. The upper side of the triangle is usually nearly 

 straight, and extends in a plane nearly at right angles to the axis of the branchlet. The 

 spines are apparently not arranged spirally, but in a typical portion are disposed in 

 longitudinal rows, five of which may be counted from one aspect. Two of these, situated 

 on the margins, have the spines at the same level ; two other rows, the spines of which 

 are again opposite, are arranged on each side of the middle line, whilst the fifth row 

 passes down the centre' of the axis in the aspect figured (PI. I. fig. 11). The members 

 of a row are two and a half to three lengths apart. 



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

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



Genus Ajrfianipathes, n. gen. 

 Antipatlies (pars), Auett. 



Corallum shrub-like with the branches free, or fan-like and reticulate. Spines usually 

 elongate, equal, or longer in the polyp areas, smooth or papillose. ' 



Polyps small and inconspicuous, often obscured by the elongate spines, which project 

 through the peristome of many species, in spirit specimens. They have a more or less oval 

 outline, the greatest diameter corresponding with the skeletal axis. The polyps are 

 separated from one another by a depression of variable extent, through which the inter- 

 zooidal communication is established by means of an axial stolon-like prolongation of 

 their ccelentera, as in most other Antipathidse. The tentacles are usually very short, and 

 project little beyond the surface of the peristome. They may, in spirit specimens, be 

 reduced to mammiform elevations of the peristome, often difficult to make out amongst 

 the projecting apices of the spines. In this genus the tentacles all arise from the 

 peristome, and have a radiate or biradiate arrangement. Spines project through the 

 soft tissues in numbers varying with the species. They often are pressed in amongst the 

 mesenterial filaments, and sometimes project into the stomodseum. In such cases each 

 spine is covered with a mesogloeal sheath clothed with entoderm, within which is the axis 

 epithelium. The mouth is usually somewhat elongated in the sagittal axis, but the 

 elongation is rarely very pronounced. There are ten mesenteries, arranged as in 

 Aritipaihes. Probably, on account of the compressed form of the polyp, the secondary 

 mesenteries are in this genus relatively more important, and reach nearly to the base of 

 the ccelenteron. 



In addition to the species which I have been enabled to study, a number of those 

 described by Pourtales, having a type of polyp which he terms " sessile," have been 

 included in the genus. The structure of the zooids of these forms is, however, not known, 



(ZOOL. CHALL. EXP. PABT LXXX. — 1S89.) Llll 16 



