132 THE BERMUDA ISLANDS. 



I was pleased to find in the Bermuda collection several 

 specimensof a form which evidently belongs to the same genus 

 as the form from the Bahamas which I described as Gemmaria 

 isolata. Several anatomical features are common to the two. 

 and I am now able to give other characteristics which may 

 serve to distinguish the genus more definitely than was done 

 in my former paper. 



The polyps of G. Rusei (PL 11, fig. 7) are solitary, being 

 attached to pebbles without the development of any coenen- 

 chyma. The specimens were obtained at North Rock, and are 

 five in number. The upper portion of the column is larger 

 than the lower, so that the polyps have the shape of a short 

 stout club ; tlie lower portion is transversely wrinkled even in 

 the expanded condition, as is noted in the label accompanying 

 the specimens. The height of the column is about 25 cm. in 

 the largest specimens; the diameter of the upper part is 0'65 

 cm. and of the lower 0'5 cm. The color/ is stated on the label 

 to have been " cinereous throughout." 



The column wall is rather thin, and is occupied throughout 

 nearly its entire thickness by foreign bodies. The ectoderm is 

 covered external^ by a cuticle, but I was unable to ascertain 

 whether a layer of mesoglcEa intervened between this and the 

 surface of the ectoderm. The structure of the thin layer of 

 mesogloea unoccupied by foreign bodies is as in other Zoanthidse, 

 and calls for no special comment. The sphincter is single, 

 and imbedded in the mesogloea; it consists for the most part 

 of a single layer of cavities, but thickens somewhat towards its 

 upper end. All the cavities contain muscle cells, there being 

 none of the empty cavities described in G. isolata. 



The tentacles are arranged in two cycles, and have onlj' a 

 very weak ectodermal musculature, as is also the case in G. iso- 

 lata. Towards the base and upon the outer surface the mesogloea 

 contains peculiar granular cells, and occasionally enclosures 

 of foreign bodies, and this likewise occurs in G. isolata. 



The disc is traversed by a number of ridges which radiate 

 from the peristome to the margin, a ridge corresponding to 



