104 CEYLON PEARL OYSTER REPORT. 



very much compressed, being somewhat triangular with a very broad base. The 

 upper margin is sub-horizontal, while the lower is convex. They are arranged in very 

 steep sinistrorse spirals and longitudinal rows, the distance between two in a row 

 being four lengths, while that between two in a spiral is one length. From one 

 aspect five can be seen quite distinctly along with the tips of other two, making in 

 all eight spines in a circumference. The spines near the base are shorter, smaller and 

 more conical. They are disposed in sinistrorse spirals and distinct rows, the distance 

 between two in a row being about four lengths. 



The polyps are typical. They are situated in a single row on the branches and 

 branchlets, and are very much elongated in the direction of the axis. The distance 

 between the polyps varies in the different parts ; they are in some places close together, 

 in others separated by intervals equal to half their length. Very often a line passing 

 through the oral cones is a line of spines, and the polyps occupy a length corre- 

 sponding to four spines in a longitudinal row. The oral cone is very prominent and 

 the mouth opening is circular. The tentacles vary in different parts according to 

 their state of contraction. The sagittal pair are inserted rather far down, corresponding 

 to spines 1 and 5 on a circumference. In some cases the tentacles have spherical 

 terminations. 



This species is chiefly distinguished by the nature and arrangement of the spines, 

 which are markedly different from those of other species, but also by the polyps, 

 which, though typical of the genus, nevertheless bear specific characters. 



Locality : Station LX. , outside pearl banks, Gulf of Manaar. 



Antipathella irregularis, n. sp. Plate, fig. 12. 



This species is represented by a small complete colony and a fragment. The 

 former is 4 centims. in height and 6 centims. in breadth, the general shape being 

 sub-flabelliform. The branches arise mostly in two planes, but occasionally in a third, 

 leaving one quadrant bare. Frequent fusions occur. 



The other specimen consists of a short main stem with a disc of attachment at the 

 base. The stem is only 2 centims. high, and the axis tapers from 1 millim. at 

 the base to a very fine point at the apex. The branches are longer than the main 

 stem and constitute the greater part of the colony. They arise on three sides at a 

 very large angle, so that the expansion is mostly lateral. 



The colour of the axis near the base is black, but it passes through a dark amber 

 to a horny yellow in the branchlets. The secondary branches are somewhat elongate 

 and slender and appear slightly flabellate. 



The spines near the base of the stem are short, conical, and irregularly disposed ; 

 but on the branches a definite arrangement can be traced. There they are compressed 

 and triangular in form, arranged sometimes in a dextrorse and sometimes in a 

 sinistrorse spiral. They are about two lengths apart and five can be seen from one 

 aspect. 



