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



Priacanthus BOOPS. 



Anthias boops (Forst.) Bloch Schn. Syst. 1801, p. 308. 



Priacanthus boops, part., Cuv. & Yal. iii. p. 103 ; Boulenger, 

 B. M. Cat. Fishes, 2nd ed. i. p. 357; Melliss. 



Priacanthus japonicus Cuv. & "Val. iii. p. 106 ; Schleg. Faun. 

 Japon., Pisces, p. 20. 



The Deep-water Bull's-eye, Melliss. 



This species is distinguished from all the others of the genus 

 by the last dorsal spine being more than twice as long as the 

 second. The membrane of the pelvic fins is black, but there is 

 little black on the sides. I saw some of these fishes caught when 

 I was out in an albacore-boat moored in about 80 fms. : when 

 alive they were of a beautiful crimson-red all over except the 

 belly, and the enormous eyes were perfectly clear and transparent, 

 fully justifying the name Bull's-eye, suggesting the convex lens 

 of a bull's-eye lantern. I opened one of the eyes and found there 

 was no black pigment visible on the inner surface, but a bright 

 silvery argenteum over the whole of the choroid. The black 

 pigmented epithelium of the retina would appear to be also 

 wanting, since, if present, it would lie in front of the choroid. 

 This condition is evidently related to vision in a dim light, and is 

 comparable to the tapetum of crepuscular and nocturnal mammals 

 such as the Felidse. It has been suggested that the retina in 

 such eyes is more sensitive in the presence of slight diffused light 

 reflected from the tapetum, but it seems possible that the tapetum 

 or argenteum may have the power of rendering dark rays more 

 visible by altering their refrangibility at the moment of their 

 impact on the tapetum which is in contact with the rods and 

 cones of the retina : in other words, the tapetum may be 

 fluorescent. 



In the British Museum Catalogue this species is not recorded 

 from the West Indies, but from the South Atlantic, S. America, 

 Cape of Good Hope, Muscat, and Japan. 



Priacanthus cruentatus. 



Labrus cruentatus Lacepede, Poissons, iii. p. 522. 



Priacanthus carolinus Less. Voy. Coquille, Poissons, p. 224. 



Priacanthus boops Val. in Webb & Berthelot, lies Canar., Ichth. 

 p. 12. 



Priacanthus blochii, part., Giinther, B. M. Cat. Fishes, i. 

 p. 218 ; Day, Fish. Ind. p. 48, pi. viii. fig. 2. 



Priacanthus cruentatus Boulenger, B. M. Cat. Fishes, 2nd ed. 

 i. p. 352. 



Priacanthus sp. ? Melliss. 



The Bull's-eye, Melliss. 



D. X, 13; Y. Ill, 14. Lat. line over 100. 



The above numbers are from a single specimen 10 inches long 

 in my collection. Both this species and P. boops are abundant 

 at St. Helena, this one being usually taken by fishing from the 

 rocks or near the shore at night, while the other is taken in deep 



