306 THE VOYAGE OF H.M.S. CHALLENGER. 



European fauna, and adds nearly 200 fathoms to its bathymetrical range, which is 

 still further increased to 533 fathoms by the dredgings of the telegraph ship " Dacia," 

 some four degrees more to the west. Judging from a figure published in La 

 Nature 1 I imagine that it was also obtained by the "Talisman" in 1500 metres off 

 flochefort. 



Among the numerous Comatulas which were dredged at Station 192 in the Arafura Sea 

 was a single mutilated specimen which has given me very great trouble (PI. LII. fig. 2). 

 Three of the rays which are preserved have bidistichate series, and the first two brachials 

 above the axillaries are clearly united by syzygy, the radiating ridges being very distinct 

 on the exposed distal faces of two of the first brachials. But I have had much difficulty 

 in determining the nature of the union between the two outer radials and the two 

 distichals respectively ; and after repeated changes of opinion, I have come to the con- 

 clusion that there is a bifascial articulation in each case. The specific formula thus 

 becomes the same as that of Actinometra pulchella, and in the absence of better 

 preserved material it seems best to refer the individual in question to this protean species. 

 The eastern form has fewer cirrus-joints, with larger and blunter spines than may occur 

 in the Caribbean type ; and the characters of the lower pinnules do not seem to be quite 

 the same in the two cases. But I have been unable to make out any differences which 

 would serve to separate the two forms specifically, though it is quite possible that they 

 may reveal themselves when better preserved material is examined. On the other 

 hand there is no a priori reason why Actinometra pulcliella, which occurs on both sides 

 of the Atlantic, should not also inhabit the Eastern seas. Another common Caribbean 

 species, Antedon carinata, is widely distributed through the Indian Ocean and also 

 occurs in the Pacific ; while Antedon quinquecostata, which was dredged by the 

 Challenger at Station 192, together with the doubtful form under consideration, is very 

 closely allied to the Caribbean Antedon spinifera. 



On the whole, then, it appears most probable that the specimen obtained by the 

 Challenger in the Arafura Sea really does belong to Actinometra pidchella, though one 

 would like to see a more perfect specimen before definitely making such a large addition 

 to the geographical range of the Caribbean type. It is also possible, on the other hand, 

 that we are here dealing with a varietal form of Actinometra macidata from Torres 

 Strait (PI. LV. fig. 2) ; but I rather doubt this being the case, as its arm-joints are 

 relatively longer than those of that type, and the terminal cirrus-joints are more com- 

 pressed laterally. The Copenhagen Museum contains a form from Bowen with very 

 much the same characters, which bears the MS. name Actinometra fusca, Liitken. This 

 may be either Actinometra pidchella or Actinometra macidata, but the question of its 

 specific identity must be left for a future decision. 



1 See H. Filhol, Explorations sons-marines, La Nature, 1884, 12 Ann. p. 32!). 



