334 Proceedings of the Royal Irish Academy. 



" The axis is calcareous, rigid, and brittle ; it is slightly oval in section ; 

 but in the younger portions it becomes quite C3'lindrieal, and tapei'S till it is 

 thread-like. It shows a veiy white core surrounded by a brownish cortex." 



The polyps are disposed in two longitudinal series on opposite faces, 

 each of which consists of from two to four irregularly alternating rows. The 

 verrucae are low and truncate; when retracted there is a deep depression in 

 the centre wliich is directed slightly upwai'ds. Tins gives a very characteristic 

 appearance (6g. 62). They are about 0'4 mm. in height and 1'5 mm. in 

 diameter at the base. 



The spicules are extremely characteristic, and quite unlike those of any 

 other species (fig. 63). They consist of the following types, with measure- 

 ments, length by breadth, in mm. 



(a) Double-clubs with almost hemispherical heads, and with a relatively 



long constriction. On either side of the constriction the large 

 warts are arranged in a whorl, while beyond tliis there is a very 

 warty hub which gives the whole head a very irregular outline : 

 008 X 004; 0-07 x 0035. 



(b) Smaller double-clubs in which the whorl is not so pronounced : 



GOT X 0-46 ; DOT x 0042. 



(c) A peculiar type, which approximate to capstans with terminal warty 



projections : 008 x 004 ; 0-07 x 0021. 

 (</) Elongated double-duba with a long, nanow constriction, with the inner 



warUs arranged appro.xiniatcly in a whorl, and with more or less 



elongated and irregularly warted hubs: 0"114 x 0053; 0'114 



X 0046 ; 0095 x 005. 

 ((•) Double-spindles (.some of the.se approach spindles). The ends are 



almost conical, and are variously covered with very irregular warts 



which give the whole a very ragged outline : 0125 x 0038, 



0-11 X 03; 01 X 0027. 

 Xofrt/i/y.— Bay of Bengal, 88 fathoms. 



XXIII. Scirpearia alba (Thomson and Henderson), figs. 64 and 65. 

 Scirpeareila alba Thomson and Henderson, xl., p. 82, PI. ix., fig. 15. 



This species was established for three long, incomplete specimens, of a 

 white colour, 28, 411, and 408 mm. in length, with a corresponding diameter 

 at the lower end of 175, 23, and 175 mm. 



Two of the colonies are unbranched ; but the largest branches at a distance 

 of 251 mm. from the lower end. 



The axis is cylindrical, hard, brittle, and very calcareous, but becomes 



