OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 31.7 



arms about 90 mm. As for the morphological characters themselves, 

 all those which the author gives may just as well apply to 0. nigra 

 which, as we shall see, shows much variation. I shall mention further 

 on a specimen from the coasts of Sicily in which the diameter of the 

 disk reaches 23 mm. ; the size given by Sars for 0. raschi is thus much 

 exceeded. 



Concerning the coloration, I may recall that it is true the disk of 

 O. nigra is generally more or less dark, usually blackish brown, but 

 Forbes has recorded an orange colored variety which is rather fre- 

 quent in the northern seas, and he has also found in the Shetland 

 Islands individuals of a very beautiful pink. On the coasts of Eng- 

 land Ophiocomina nigra appears capable of descending to depths 

 as great as those recorded by Sars on the coasts of Norway, and it 

 has been captured at all depths between sea level and 146 meters (80 

 fathoms) (see F. Jeffrey Bell, '84, p. 129). 



I have had the opportunity of studying some specimens from the 

 Faroe Islands collected by Doctor Charcot in which the disk is very 

 light gray, with the spines almost white; I am speaking of alcoholic 

 specimens, for the coloration in life was not noted ; but it is very 

 probable that the color was lighter than usual, for in the specimens 

 of O. nigra in alcohol which I possess from the coasts of England 

 and France the disk always shows a more or less dark brownish or 

 brownish yellow coloration. 



As for Ophiocomina tumida, this species was created by Miiller 

 and Troschel, who only published a very short description of four 

 lines, in which they mention four arm spines only, and as the habi- 

 tat Genoa, Lyman ('65, p. TO) says on this subject: "The original 

 in the Leyden Museum is marked 'Gulf of Genoa,' but this looks 

 like a mistake. I do not remember to have seen any Ophiocoma at 

 all from the Mediterranean," etc. 



But many years ago I received from my excellent colleague, Prof. 

 A. Russo, an ophiuran from the coast of Sicily which he asked me 

 to determine for him and which I assigned without hesitation to 

 O. nigra. This specimen, of which I figure here the ventral surface 

 (pi. 75, fig. 4), is of very large size; the diameter of the disk reaches 

 23 mm. ; the arms, which measure 4 mm. in width at the base, are in 

 fragments, but their total length may be estimated as 100 mm.; 

 the dorsal surface of the disk is of a rather dark brown; that of the 

 arms is lighter, and the spines are yellowish. 



The occurrence of 0. nigra in the Mediterranean should not be 

 surprising, for this species occurs also at the Azores, where it was 

 found by the Princesse Alice. I include some photographs showing 

 two specimens from this latter locality (figs. 1, 2, 3). 



To complete these comparisons, I give a photograph of the ventral 

 surface of a specimen from Roscoff (pi. 75, fig. 5). I believe that 



