130 Dr. Strethill Wright's Observations on 



were mistaken for a mass of minute ova. These envelopes cover 

 the whole of the body of the polyps up to the border of the 

 mouth, and consist of an exaggerated development of the gela- 

 tinous coat which probably exists on the polypidom and body of 

 all the Hydroidse, in some as a delicate epidermis, in others (as 

 in Bimeria vestita and the subject of this notice) as a thick, 

 imputrescible coat — the '^ coUetoderm." 



The Medusoids (PI. IV. fig. 7) are of great size when com- 

 pared with the very minute polyp, and resemble exactly those of 

 Atractylis repens. I have not witnessed any further development 

 in them after their separation from the zoophyte. In those of 

 A. repens, when kept alive for some time, the two tentacular 

 tubercles put forth short tentacles, and four other tubercles ap- 

 pear on the marginal canal, as shown in fig. 8, — a change ana- 

 logous to that undergone in Bougainvillea Britannica. 



Atractylis coccinea, n. sp.* 

 Polypidom creeping, widely reticulate. Polyp fusiform, set at an 



obtuse angle to its stalk, rich crimson or pink, with eight 



alternating tentacles, four long and four short. 



This zoophyte was found at Inch Garvie in August last, grow- 

 ing on the roots of Laminaria saccharina. The polypary consists 

 of an open network of milk-white fibres, which closely invests 

 the branches of the root. From this network the polyp-stems 

 are given ofi^, each about a quarter of an inch in length, of a rich 

 pinkish cream-colour, and bearing at its summit a single crimson 

 polyp with a double i"0w of transparent colourless tentacles. The 

 body of the polyp is fusiform, sometimes nearly cylindrical, and 

 consists of an endoderm having its cells laden with granules of 

 the richest carmine-colour, covered by an ectoderm of transpa- 

 rent white — a white blond dress over a crimson satin petticoat. 

 The polyps, like others of this class, have the habit of turning 

 themselves inside out, when the internal surface of the deep- 

 coloured velvety endoderm is readily observed. On such occa- 

 sions masses of granular matter are frequently ejected, which 

 are composed of small pigment-globules filled with crimson fluid. 

 The tentacles are eight in number, four of which are long and 

 held nearly erect, and alternate with the rest, which are shorter 

 and more expanded. The thi-ead-cells are inconspicuous. 



This beautiful little zoophyte, when seen with a single lens, 



presents a perfect garden of minute animal flowers covering the 



roots of the sea-weed. The reproductive apparatus was not 



observed. . . 



Hydractiraa echinata. 



In afoi'mer number of this Journal (vol. iv. ser. 3. p. 50) Prof. 



AUman has remarked, with regard to Hydractinia, that " the 



* Read to the Royal Physical Society of Edinburgh, Feb. 27, 1861. 



