118 MR. J. T. CUNNINGHAM ON MARINE FISHES [Jan. 18, 



he depressed by first pushing back the slender second spine. (See 

 Otto Thilo, Journ. Anat. and Phys. vol. xxxv. p. 207.) 



This species is widely distributed, occurring in the West Indies 

 (Jamaica), Zanzibar, the coast of China, Sandwich Islands, 

 St. Paul's Rocks, and Ceylon. 



OSTRACION QUADRICORNIS, Var. NOTACANTHUS. 



Ostracion quadricomis Linn. Syst. Nat. i. p. 409. 



Ostracion lister Lacep. i. p. 468, pi. 23. fig. 2. 



Ostracion notacanthus Bleek. Ned. Tijds. Dierk. ii. p. 298, fig. 



Ostracion quadricomis Bleek. Atl. Ichth. v. p. 32. 



Melliss states that this fish is not very common at St. Helena, 

 but I found it quite common although not so abundant as the 

 cunning-fish, with which it was usually to be seen swimming 

 about the landing steps of the wharf. I caught specimens with 

 a rod and line using a small hook and mackerel as bait. It was 

 of a beautiful blue colour when first caught, each hexagonal 

 scute having a spot of darker blue in the centre. All that I saw 

 had the spine on the dorsal edge which distinguishes the variety 

 notacanthus, which is peculiar to St. Helena. 



The species is confined to tropical parts of the Atlantic, 

 and occurs at the Bermudas, West Indies, coasts of Brazil, 

 Ascension, and West Africa. A specimen from Rio Janeiro 

 in the Museum has no dorsal spine ; Giinther remarks that 

 specimens from the West Indies often have an indication of 

 this spine. In all cases the spines are outgrowths of the centres 

 of single scales, although the dorsal spine and the two ventral 

 spines suggest the idea that they are the vestiges of the first 

 dorsal and the pelvic fins. 



Bleeker considers the notcccanthus of St. Helena a distinct 

 species, although he says that the dorsal spine exists sometimes in 

 quadricomis ; but he says there are other differences : the back in 

 quadricomis is more compressed and more elevated, the profile more 

 perpendicular, the eyes smaller, the head smaller, the scutes of 

 the side more numerous, and a spine at the end of the carapace 

 above the caudal peduncle. A very good figure of the St. Helena 

 variety is given by Bleeker. The colours are apparently from a 

 spirit specimen, as I find the characteristic blue colour which I 

 saw in the fresh specimens at St. Helena vanishes after they have 

 been in spirit. 



Tate Regan (Proc. Zool. Soc. 1902, ii. p. 291) adopts LactopJirys 

 Swainson (Lardner's Cyclopaedia, Fishes, vol. ii. 1839, p. 324) for 

 those with only three ridges, and makes Ostracion four- or five- 

 sided. But the original Ostracion of Linnasus was three-sided. 



Tetrodon cutaneus. 



Tetrodon cutaneus Giinther, B. M. Cat. Fishes, viii. p. 287 

 (1868). 



This species was named by Giinther, and has been found only 



