302 CEYLON PEARL OYSTER REPORT. 



covered with numerous rough warts. Their measurements, length by breadth in 

 millimetres, are as follows: 1'6 X 0'2 ; 0'8 X 0'14; 1 '3 X 0'2 ; 0'9 X 0'16 ; 

 0-25 X 0-06; O'l X 0'02 ; 2'1 X 0-20. 



In the complete colony the outer spicules often *t retch the whole distance between 

 the polyps. In certain conditions of the polyps there appear to be 8 projecting 

 spicules on each calyx. 



Localities : Deep water outside pearl banks, Gulf of Mannar ; and deep water off 

 Galle and onwards up West Coast of Ceylon. 



Muricella ceylonensis, n. sp. Plate VI., fig. 4. 



The colony is branched in one plane, with a strong tendency to anastomosis even 

 between twigs of different main branches. It measures 12 centims. in height by 

 8 centims. in breadth. Most of the twigs arise at right angles from the main branches 

 and almost all the short ones remain perpendicular. Many arise in opposite pairs, 

 others are alternate, and in other regions the twigs may be restricted for an inch or 

 more to one side of the branch. A common interval between the origin of two 

 adjacent branches on the same side is 4 millims. The verrucae stand out prominently 

 at right angles to a height of about 0'5 millim., and the interval between two on the 

 same side is on the average 1 millim. The surface of the colony is covered with huge 

 white spicules readily visible to the naked eye. Spicules slightly curved at the base 

 run up the sides of the verruca, and their tips project at the mouth. The black 

 horny axis measures 2 millims. in diameter at the base, it tapers to a diameter of 

 O'l millim. at the tips of the twigs, and in these delicate parts it shows a brownish 

 tint. The general colour of the colony is grey. In another specimen measuring 

 8 centims. by 6 centims. the colour was whiter owing to the more densely packed 

 large spicules; there was no hint of anastomosis, and the perpendicular mode of 

 branching was not so pronounced. 



The spicules, which are longitudinally disposed, are straight or curved, densely 

 tuberculate spindles, the largest of which seem here and there to be disposed in 

 definite strands or lines. They vary in size from 3'5 millims. to 0'35 millim. 



Compared with M. ramosa this species is much less thickly branched; it shows 

 much less anastomosis, it bears polyps at wider intervals, and has larger spicules. 



Muricella nitida, VEKBILL. 



This species is represented by a colony with a maximum height of 105 millims. and 

 a maximum width of 80 millims. The base consists of a broad flattened portion from 

 which the fan-shaped colony rises. The axis is dark brown, almost black in colour in 

 the lower parts, but it becomes yellowish in the upper portions of the branches and in 

 the twigs. It has a basal diameter" of 2 millims. 



The branches, which are confined to one plane, come off' at an angle which 

 approaches a right angle and then bend upwards, so that they appear to be parallel 



