110 Proceedings of the Rojial Irish Academy. 



The total height of the colony is 31 cm. ; it consists of a main stem 

 30 cm. in height, from which four branches arise, all on one side. The first 

 arises at a point 4 cm. from the base ; and the others after 2-5, 3, and 10 cm. 

 consecutively. The lowest branch is broken, and is 13 cm. in length, but 

 was evidently much longer ; the others are 5-5, 10, and 15 cm. respectively 

 (fig. 1051. 



The main stem after the origin of the first branch and all tlie branches 

 are markedly flattened in the plane of ramification. 



The diameter of the main stem near the base is 2 mm., and its greatest 

 breadth in the flattened portion 3 mm. The branches vary considerably 

 in thickness. The colour of the colony is a pale orange-yellow ; but the 

 verrucae are more reddish. The coenenchyma has a very granular surface ; 

 it is nearly 1 mm. in thickness in the branches, but thinner in the older 

 parts, where the axis is proportionately larger. 



The polyps occur on the branches and also on the main stem, except on 

 the portion below the origin of the first branch ; they are distributed in two 

 longitudinal series on tlie sides of the branches ; the flattened aspect is broad, 

 and quite devoid of polyps. In each series this is a single row ; but over- 

 crowding or the interposition of young forms sometimes obliterates the 

 symmetry (fig. 106). 



The verrucae, when retracted, are low, truncated cones, and often show 

 very distinct wrinkling ; they project very little beyond the coenenchyma. 

 Many of the anthocodiae are only partially withdrawn ; and the infolded 

 tentacles appear to form a cone ; on further retraction their bases foi'm a 

 horizontal pseudo-operculuni, and the verrucae present a very shrunken 

 appearance. The tentacles are eventually quite covered up by the inturued 

 sides of the verrucae. 



The canal system is typical and well defined ; the two main canals, 

 corresponding in position to tlie bare tracts, are large ; and a depression is 

 sometimes visible owing to a collapse of the walls. 



The axis is thin, cylindrical, composed of concentric laminae, and markedly 

 calcareous. It is yellow in colour; and the surface is striated, two grooves 

 slightly larger than the others being seen in some places. 



The spicules (fig. 10*7) consist of the following types, with measurements, 

 length by breadth, in millimetres. 



(«) Double-clubs, with a short constriction and with almost hemispherical 

 heads, very irregular in outline, covered with few large warts: 

 0-08 X 0-042; 0-076 x 0-046; 0076 x 042. 



(i) Elongated double-clubs, with rounded ends, and openly-warted : 

 0-08 X 0-038 ; 008 x 0-034. 



