less distorted ; the edge is more raised above the surface of the coral than in 5. tiliatus. The 

 diameter of the cyclosystem is i by 0,8 mm. The septa are very thick, the space between them 

 narrow. The ampullae appear lirst on the posterior surface of the flabellum, onc below each 

 cyclosystem; later they are formeel on the anterior surface or sides of the branches, but always 

 in connexion with a cyclosystem. The surface ot the ampullae is very irregular. 



This species may be defined : 



Hydrophytum flabellate; surface covered with large blunt spines ; cyclosystems directed 

 towards one surface; gastropore deep and curved down the stem. 



At first sight S. tiliatus and 5. umbonatus, owing to the peculiar position of their cyclo- 

 systems and the shape of the gastropore, appear to belong to a different genus to the other 

 species of Stylaster. But in 5'. multiplex and S. minimus we have intermediate forms connecting 

 these with the ordinary types of Stylaster. In the former 5". multiplex, the cyclosystems are 

 partially turned towards one surface of the flabellum and in the latter, S. minimus, although the 

 cyclosystems face towards one surface only, the gastropores are not very deep ancl curved, as 

 in 5. tiliatus. These two characteristics cannot then be depended upon for generic distinctions. 



The genus Stenohelia was defined by Moseley in the following terms : "Corallum delicate, 

 branching, flabelliform ; pores in regular cyclosystems only. Cyclosystems all turned towards one 

 surface of the flabellum. Dactylopores without a style or with a very rudimentary one. Gastro- 

 pore very deep and curved, so as to tubulate in all but the older branches, the entire lengths 

 of the axes of the branches, with small styles seated at the bottoms of those tubes and directed 

 parallel to the axes of the branches at right angles to those of the mouths of the cyclosystems". 

 If we are right in concluding that the shape and position of the cyclosystems as they are here 

 described (which description also applies exactly to 5". tiliatus and S. umbonatus) are not good 

 characters for generic distinction, then the only character that divides the genus Stenohelia from 

 Stylaster is that the dactylopore in the former is either without a style or with a very rudimentary 

 one. The small size of Stenohelia profunda must have made it difficult to ascertain this point 

 with certainty. 5. umbonatus is a larger and 5. tiliatus a very much larger species and these 

 both show a distinct style in the dactylopore, which can in neither case be called rudimentary. 

 It seems therefore that there is not sufficiënt reason for keeping separate a genus Stenohelia, 

 and so the new species 5. tiliatus and 5. umbonatus have been included in the large and variable 

 genus Stylaster and according to us the only two species of Stenohelia, S. madierensis Kent 

 and S. profunda Moseley, must also be added to it. Johxston, who first described the species 

 S. madierensis placed it in the genus Stylaster : it was afterwards redescribed by Saviixe Kent. 



Errina Gray. 



The genus Errina may be defined as follows : 



Coenosteum arborescent, irregularly flabellitorm ; gastropores ancl dactylopores separate, 

 not in cyclosystems, regularly or irregularly arranged; style in gastropore, no style in dactylopore; 

 dactylopore on a nariform projection; gastropore with or without a scale (the raised margin of the 

 pore or fused dactylopore projections). Gastrozooids with four or five short tentacles; dactylozooids 



S1BOGA-EXPEDIT1E VIII. -■ 



