3 1 8 Proceedings of the Royal Irish Academy. 



The coeueuchyma is moderately thin and finely granular ; the general 

 colour of the colony is orange-yellow ; but the verrucae are reddisli. 



The polyps are confined to two longitudinal, lateral tracts, separated by 

 two bare spaces. Near the base of the colony, and also in the younger part 

 near the tip, there is a single row of polyps in each series ; but in the middle 

 part there are two irregular rows, owing to crowding and the interposition 

 of young polyps. 



The verrucae, when only partially retracted, are cylindrical, elongated, 

 and slightly turned towards the coeueuchyma (fig. 34&). Near the base 

 (fig. 34a) and the tip (fig. 34c) they are almost completely retracted, and then 

 appear as low warts, and may even be sunk within pits in the coenenchyma. 

 The great majority of the verrucae are directed upwards, but some are 

 tui-ned downwards. When expandeil they are about 12o mm. in height and 

 1 mm. in diameter at the base. 



The canal system is typical ; the two main longitudinal canals are only 

 slightly lai-ger than the others. 



The axis is cylindrical, tapers only slightly, and is calcareous. The 

 colour varies from brown to yellow ; the surface is marked by faint longi- 

 tudinal striae. 



Tiie spicules of this species (fig. 35) are very characteristic. They consist 

 of double-clubs, double-spindles, and some which approach spindles. They 

 are not densely covered with warts ; wliile the warts themselves are only 

 slightly papillose. 



Tlic following are the chief tjrpes, with measurements, length by breadth, 

 in millimetres : — 



(n) Small double-clubs, with almost hemispherical ends, and irregularly 

 coveretl with small papillose warts and with a short, broad con- 

 striction : 0-061 X 0042; 006 x 004. 



(b) Slightly elongated double-clubs very openly warted and with relatively 



blunt ends: Oil x 006; 0-095 x 0-046; 0099 x 0049. 



(c) More elongate<l double-clubs, approaching double-spindles and even 



spindles. The cuds are markedly conical, and the constriction is 

 more or less definite : 0015 x 0-034; 0-08 x 0-03. 

 Locality. — Andamans. 



Pectlvata GitOUP. 



This group is easily distinguished by the character of the spiculation, but 

 also, and more readily, by its unique type of branching. 



