CLAKK: AUSTRALIAN AND IN DO-PACIFIC ECI1INODERMS. 123 



Ophiarachnella gorgonia. 



Ophiarachna gorgonia Miiller and Troscliel, 1842. Sys. Ast, p. 105. 



Pectinura gorgonia Liitken, 1869. Add. Hist. Oph., 3, p. 33. 



Per.tinura marmorata Lyman, 1874. Bull. M. C. Z., 3, p. 222, pi. 5, figs. 1-7. 



Pectinura ramsayi Bell, 1888. Proc. Zool. Soc. London, p. 281, pi. 16, figs. 1, 2. 



Pectinura intermedia Bell, 1888. Proc. Zool. Soc. London, p. 386. 



Pectinura Stearnsii Ives, 1891. Proc. Acad. Nat. Sci. Philadelphia, p. 212, pi. 11, 



figs. 1-5. 

 Pectinura venusta de Loriol, 1894. Mem. Soc. Phys. et Hist. Nat. Geneve, 32, pt. 1, 



no. 3, p. 16, pi. 23, figs. 3-3h. 



Natal ; Mozambique ; Zanzibar ; Madagascar ; Mauritius ; Ceylon ; Madras ; 

 Pondicherry ; Andaman Islands ; Nossi-Be ; Tonquin ; Pelew Islands ; Philippine 

 Islands; southern Japan ; Amboina and 15 other stations in Dutch East Indies ; 

 Sorong, New Guinea ; New Caledonia ; Torres Strait ; Port Jackson, N. S. W. ; 

 Turtle Bay, southern West Australia ; Fiji Islands ; Gilbert Islands ; Samoa. 

 Littoral to 155 fms. 



The M. C. Z. collection contains 59 specimens of an ophiuran which, while 

 showing great diversity in size and color, are so alike, or intergrade with each 

 other so completely, in form, proportions, granulation, scaling, arm-plates, oral 

 shields, arm-spines, etc., that I am entirely unable to distinguish more than 

 a single species. This series includes a specimen from Mauritius which answers 

 almost exactly to de Loriol's description and figures of 0. venusta ; Lyman's type 

 and co-types of 0. marmorata from the Philippines; specimens from Port Jack- 

 son, sent by the Australian National Museum, labelled 0. marmorata (3), 0. ram- 

 sayi (3), and 0. gorgonia (1) ; and numerous specimens labelled 0. gorgonia by 

 Lyman. After a very thorough study of this material, I am unable to satisfy 

 myself that any of the above-named species can be distinguished from 0. gorgonia. 

 It would be hai-d to pick out three specimens of Ophiarachnella which look more 

 uidike superficially than a typical gorgonia var. viridis Brock, an 0. marmorata 

 from the Philippines, and an 0. marmorata from Port Jackson, the coloration is so 

 strikingly different ; and yet when one attempts to separate them in any other 

 way than by color and size it proves to be practically impossible. I am therefore 

 forced to the conclusion that the 59 specimens before me represent a single 

 species, very variable in color and size, and showing more <or less diversity in its 

 structural characters. Furthermore, I fail to find any character by which 0. in- 

 termedia Bell is to be distinguished, and I believe the type of 0. stearnsii Ives is 

 simply an exceptionally large individual of the same species. I am confirmed in 

 this opinion by the fact that such a keen observer as Brock collected only 0. gor- 

 gonia during his stay in the East Indies, not finding any specimens which he could 

 separate as 0. marmorata, autc, and further by the even more remarkable fact 

 that Koehler, in all of the immense amount of material which has passed through 

 his hands in the past twenty years, including the " Investigator" and " Siboga" 

 collections, has not discovered any specimens of 0. marmorata, autc. to be dis- 

 tinguished from 0. gorgonia. It is nevertheless quite possible that in the light 



