1 08 Proceedings of the Royal Irish Academy. 



XXYII. Scirpearia ramosa n. sp. Figs. 102-104. 



In the Littoral Collecriou of the Indian Museum there occurs a very- 

 beautiful and characteristic branched colony for which it has been necessary 

 to establish a new species. The mode of branching, the nature of the 

 verrucae, and the distinctive character of the spicules, are all features of 

 great importance. The colony is complete with its basis of attachment ; it is 

 14 cm. in height and about 9o cm. in maximum breadth, and is branched 

 irregularly in one plane. The majority of the branches arise at nearly right 

 angles ; they are long, and may ascend for a considerable distance without 

 giving rise to finer twigs. They vary very little in diameter throughout 

 their entire length (fig. 102). They are flattened in the plane of ramification, 

 so that a cross-section is elliptical. The diameter of the main stem is 

 2*5 mm., but some of the branches are 3 mm. in their longer and about 2 mm. 

 in their shorter diameter. 



The coeneuchyma has a very granular surface ; it is 1 mm. in thickness 

 towards the tip of the branch, but considerably less in the older parts where 

 the axis is thicker. 



The colour of the colony in spirit is yellowish-red ; but the verrucae are of 

 a more decided reddish tint, and streaks of red pass indefinitely from them, 

 and gradually merge into the general tone of the coenenchyma. When dry 

 the whole colony is almost ochreous yellow. 



The polyps occur on the branches, but not on the main stem ; they are 

 distributed in two distinct series on the sides, or non-flattened aspects, of the 

 branches ; but occasionally they encroach on the flattened surfaces. There 

 are thus two very distinct bare longitudinal zones. 



The verrucae have the appearance of very low truncated cones, and are 

 almost crater-like ; they hardly project beyond the coeneuchyma. This is 

 due to their great contractility, as is evident from the shrunken appearance. 

 They are about 0-5 mm. in height and 2 mm. in diameter at the summit. 

 The oral opening is very large ; it is circular in outline, and the eight 

 retracted tentacles apparently form a pseudo-operculum (flg. 103). 



The canal-system is typical of the group ; the two main canals are very 

 large, and correspond to the bare tracts. On several of the branches there 

 is a distinct longitudinal furrow indicating their exact position. 



The axis is cylindrical, and is composed of definite concentric laminae ; a 

 cross-section shows lines radiating from the centre to the circumference. The 

 outer more horny portion is brown in colour, but the more calcareous central 

 part is white. The surface is marked by longituiliual ridges and furrows, the 

 number of which varies according to the portion of the colony examined. Two 



