E0H3 NODE RM ATA. 125 



7. Linckia marmorata. 



Ophidiaster marmoratus, Michelin, Mag. Zool. 1845, Zooph. p. 21, pi. 10. 



Linckia marmorata, Perrier, p. 13o. 



If I am correct in referring to this species a serios of specimens 

 from Port Molle and Fitzroy Island, it will be easy to understand 

 how it is that M. Michelin's species was never again recognized till 

 the Paris Museum came into the possession of his type ; that would 

 appear to be the only oxample that they possess, and, as M. Perrier 

 points out, the " typo " is obviously young. The specimens before 

 me are clearly enough all representatives of the same species ; but 

 were any one of them described it is quite possible that from the 

 description alone of that single specimen it would be easy to regard 

 some others of the series as belonging to another form. 



In the first place, though all the specimens are provided with the 

 intermediate plate that connects into a pentagon the terminal one of 

 the " rangee de plaques qui occupe la ligne median© dorsale de 

 chaque bras," the extent to which this is evident varies a good deal 

 and one would hardly think it worthy of especial note in the largest 

 example were not attention directed to it by the better-marked 

 characters of some of the smaller. Secondly, the smallest specimen 

 has the dorsal plates covered with coarse granulations ; of some of 

 these, at any rate, it would be appropriate to say (again quoting 

 Perrier) " les granules voisins de leur centre sont un peu plus gros 

 que les autres ;" on the other hand, one, two, or more Granules 

 near the centre acquire, in the larger specimens, a much greater 

 predominance, and give a somewhat different appearance to the 

 creature ; in the largest specimen these again have disappeared, and 

 the whole surface of the plates is more uniformly granular. Thirdly 

 the dorsal plates may lose the regularity of outline which is so well 

 marked (if not exaggerated?) in Michelin's figure, and which is 

 expressed by M. Perrier in the words " sensiblement carre'e," and 

 become narrower at the angles at which the pores are placed ; this 

 is perhaps due to the greater development in the number of pores 

 of which as many as seven may in some cases be found within the 

 limits of one area. Lastly, it is only in the smallest specimens that 

 we find a double row of tubercles fringing the adambulacral spines ; 

 in all the larger specimens the row is single, or, in other words one 

 row of tubercles ceases to grow proportionately, and becomes ob- 

 scured in the general granulation of the actinal surface. 



The only considerable point of difference between these specimens 

 and that figured by Michelin lies in the remarkable coloration of 

 his specimen ; if, however, M. Desjardin's example from the island 

 of Mauritius was immediately dried, it might have retained its colour s 

 while Dr. Coppinger's specimens, which were placed in spirit, mio-ht 

 very possibly have had part of their colouring-matter dissolved out. 

 The largest example has R equal to 50 millim. 



Prince of Wales Channel, 7 fms. 



