66 Proceedings of the Royal Irish Academy. 



XV. — Scirpearia profunda (Wright and Studer). Fig, 27. 

 Scirpearella profunda Wright and Studer, 1., p. 155, PI. XXXI., fig. 2 ; 



Ph xxxii., figs. 1 and 1« ; PL xxxiv., fig. 7. 

 Scirpearella gracilis Wright and Studer, 1., p. 156, PI. xxxi., figs. 1 and In ; 



PI. XXXIV., fig. 6. 

 Scirpearella rubra Wright and Studer, 1., p. 157, PI. xxxiv., fig. 5. 

 ScirpeareJla moniliformc Thomson and Henderson, xL, p. 82. 



We have examined the type specimens in the British Museum of these 

 three species, and have come to the conclusion that they cannot be regarded 

 as distinct. S. rubra is undoubtedly the same as S. gracilis ; but S. profunda 

 difters in that it is branched. When we take into consideration, however, 

 the great length of the tiagelliform branches of S. profunda, we are quite in a 

 position to conceive the longest fragment of S. gracilis as a portion of a 

 branch of a much larger colony than that formed by S. profunda. These two 

 species, as Wright and Studer observe, " were taken at the same haul of the 

 dredge from a depth of 130 fms. ; although, no doubt, closely related forms, 

 there seem sufficient differences to justify their being for the present treated 

 as distinct." 



The spiculation is essentially the same in all three species ; and the nature 

 and distribution of the verrucae show variations not greater than those in 

 other cases of specimens undoubtedly belonging to the same species. For 

 this reason we feel justified in merging the three species under the earliest 

 name, S. profunda. 



The following are the chief characteristics of the different tj-pes : — 



6". pi-ofunda. — The colony is feebly branched. The axis is calcareous, 

 brittle, and of a circular outline, with some spiral grooves; it is formed of 

 several concentric calcareous layers, which easily peel off. 



The polyps are in irregular spirals on the stem and branches, from 2 mm. 

 to 3 mm. apart, but closer to one another towards the termination of the 

 branches. The older verrucae are more conical than the younger ones. 

 When fully retracted they are oblong conical. 



The coenenchyma is moderately thick and finely granidar. 



The colour in spirits is a whitish-brown. 



Loc'ditij. — "Challenger" Station 177, off the Xew Hebrides; depth, 

 130 fms.; bottom, volcanic sand. 



<S. gracilis. — Colony is simple, so far as can be judged. 



The axis is calcareous and very brittle ; it is grooved. The polyps are 

 crowded on the stem in four rows, the polyps in one row alternating with 

 those in the next row, so as to give a more or less spiral arrangement to the 



