580 



COLLECTIONS FROM THE WESTERN INDIAN OCEAN. 



apical diameter about '75 millim. ; anterior and posterior faces 

 scarcely distinguishable ; verrucas subscrially arranged down the 

 lateral margins, more sparingly on tbe anterior and posterior aspects, 

 distance apart 1-1 "5 millim. (the latter is the interval characteristic 

 of the anterior and posterior sides of the branches ; this interval also 

 occurs occasionally on the sides). Colour, in spirit, deep umber- 

 brown, almost black. Surface between verruca) minutely granular. 

 The spicules have their tubercles closely aggregated, prominent 

 (•04-'05 millim. high), broad (about •Ol-'Oo millim.), and very richly 

 and minutely tuberculate and frequently compound (branching) ; the 

 general outline of the spicule is a rude oval, flattened parallel to 

 the long axis, with the ends broad, but one end tends to be sub- 

 globose, while the other is constricted, forming a kind of handle; 

 size of spicules about '19 by '14 millim. 



Hab. Providence Reef, Mascarene Islands, 24 fms. ; bottom, sand 

 and dead coral. 



This species is related not distantly to Muricea umbraticoides, 

 Studer, from which it differs chiefly in its erect and more slender 

 habit, in the shorter and less regularly formed spicules, and in their 

 longer and more ragged tubercles. 



The height of the single specimen (which is preserved in spirit, 

 divides three times, and has a slight spreading base) is 70 millim. 

 (nearly 3 inches). As it is well preserved and apparently normal 

 in growth, I have ventured to give it a distinctive name. 



21. perramosa, mihi (Ann. & Mag. iS"at. Hist. 1882, x. p. 128*), 

 from Mauritius, the only other nearly allied form described from the 

 Western Indian Ocean, is at once distinguished from it by the red 

 colour and much-branched habit. 



GORGONELLIM1. 



6. Juncella gemmacea, Milne-Edwards 4' Haime. 



Several specimeus, dry and in spirit, of the deep scarlet form, 

 which was the most abundant in the jSorth- Australian collections 

 of the 'Alert.' 



Hab. Providence Island, Mascarene Islands, 19 fms. 



MELITTLMIDM. 



Melithseadae and Mopselladee, Gray, Cat. Lithoplujt. Brit. Mus. 

 pp. 3-12. 



WRIGHTELLA. 



Gray, op. cit. p. 31. 



Mopsea (part.), Ehrenberg, Cor. roth. Meer. p. 131; Klunzinper, Eor. 

 roth. Meer. p. 57. 



This genus is closely allied to Mopsella, Gray, having " Blattkeule" 



* The branches as there described are much too slender ; the figure is, 

 however, correct; the primary branches measure 7, the terminal twigs 75 

 millim. in greatest diameter, excluding verruca. 



