114 MR. J. T. CUNNINGHAM ON MARINE FISHES [Jan. 18. 



Rhombus rhomboides Bonaparte, Fauna Italica., iii. Pesci, 

 1832-41 (male). 



Rhombus podas, ibid, (female). 



Rhomboidichthys mancus Giinther, B. M. Cat. Fishes, iv. p. 432, 

 1862 (male). 



Rhomboidichthys podas, ibid, (female). 



Boihus podas Steindaehner, lchth. Bericht. Sechste Fortsetzung, 

 S.B. Akad. Wien, 1868. 



Rhombus maderensis Lowe, Proc. Zool. Soc. 1833, p. 143. 



Rhombus serratus Valenciennes in Webb & Berthelot, lies 

 Canar., Poissons, p. 82, 1835-50. 



Platophrys podas Jordan & Goss, Flounders &. Soles Amer. & 

 Europe, Bull. U.S. Fish. Comm. for 1886 (1889). 



Rhomboidichthys sp., Melliss. 



The specimens which I brought back from St. Helena are 8 in 

 number, 4 large males, 2 large females, and 2 smaller females ; 

 the largest male is 8| ins. long, the largest female 8| ins. ; the two 

 smaller females are 6| and 6g ins. respectively. In the males 

 there is a spine on the anterior end of the maxilla and another on 

 the antero-superior angle of the lower orbit, also one on the 

 antero- inferior angle of the upper orbit, but this last is less 

 prominent. As in other cases of sexual dimorphism the male 

 characters are slightly developed in the largest females ; in this 

 case the interorbital space is greater than the diameter of the 

 orbit but much less than in the adult male. The colour of the 

 St. Helena specimens is very dark, almost black, marked with 

 ocelli consisting of rings of minute bluish-white spots ; no dark 

 spot on the lateral line is visible. In the British Museum is a 

 specimen from Ascension, 8| ins. long, much lighter in colour 

 than my specimens and with much more conspicuous ocelli ; it 

 is labelled R. ocellatus but is certainly of the same species as 

 mine, the true ocellatus of Agassiz having the pectoral elongated 

 in the male, while in podas it is not elongated. I have no doubt 

 that the various species of the genus described under different 

 names from the Mediterranean, Madeira, and the Canaries are all 

 one species and that the species found at St. Helena and Ascension 

 is the same, but in some of these localities there appear to be local 

 peculiarities which must be considered. In the British Museum 

 specimens from St. Helena collected by Melliss are labelled by 

 Dr. Giinther R. mancus var. The dark colour of the St. Helena 

 specimens is evidently due to the dark volcanic material of which 

 the sea-bottom consists, and is probably not permanent since we 

 know that flat-fishes change their colour according to the ground 

 on which they live ; this darkness conceals the characteristic 

 black mark on the lateral line, which cannot therefore be said to 

 be absent. Mediterranean examples in the British Museum are 

 old and not in very good condition, but those from St. Helena 

 agree closely with the figures given of Mediterranean specimens 

 by Bonaparte in his ' Fauna Italica.' The St. Helena examples 

 seem, however, to reach a larger size ; Bonaparte states that the 



