during their Growth and Development. 117 



Mediterranean, combined with the statements contained in 

 literature, has led to a fresh examination of a question which 

 has also been raised elsewhere — namely, whether Zeusfaher 

 axi^ Z. pungio must really be considered distinct species, or 

 only varieties with a more or less local character. It is 

 clear that the differences which have been appealed to are not 

 characters relating to sex or age ; but at the same time it re- 

 sults, from the examination that I have made, that Z. pungio 

 can, at the utmost and even with difficulty, be regarded only as 

 a variety of Z. faher^ and by no means as a distinct species — 

 an opinion which seems to be shared by the greater number 

 of the Italian ichthyologists. The only somewhat constant 

 character is the form and size of certain scutes at the base of 

 the second dorsal. On the other hand, I must maintain that 

 Z. ausfralis, Rich. (Australia), is a perfectly different species 

 from Z. faber, but perhaps identical with Z. japonicus j 

 whether Z. capensis is a third species, or to be combined also 

 with Z. nustralis, is a question still to be solved ; in any case 

 it will belong to a species distinct from Z.faber. It is no 

 doubt with good reason that Mr. Gill has established the 

 genus Zenopsis for the species more exclusively inhabiting 

 the deep waters (which can hardly be said of the true species 

 of Zeus), such as Z. conchifer (Madeira, with Z. ocellatus of 

 North America) and Z. nehulosus (Japan) ; but the riglit of 

 these species to be considered distinct still needs revision ^ 

 which is the more necessary as the characters indicated are of 

 rather doubtful value, and as we have here to do with species 

 inhabiting the great depths of the oceans, and the geogra- 

 phical distribution is often very extensive in the fish of this 

 category. I shall refer finally to the note by Dr. Gilnther on 

 a supposed juvenile form of Mene macidata, a note which is, so 

 to speak, tlie harbinger of the interesting particulars which 

 the future will no doubt bring us as to the hitherto unknown 

 metamorphoses of the genera Zeus and Lampris. 



14. PsETTUS J Zanclus and Gnathocentrum ; Platax. 



Dr. Giinther has already demonstrated that Gnathocentrum^ 

 Guich. {Zanclus canescens, L.), is only a young form of 

 Zanclus cornutus ; nevertheless the late M. Bleeker, in his 

 * Atlas Ichthyologique,' still separates them as distinct species. 

 I have therefore thought it right to state that for me also it is 

 an established fact that the genus Gnathocentrum and Z. canes- 

 cens are respectively only the young stages of the genus 

 Zanclus and of Z. cornutus. 



Other authors have already pointed out that it is an error 

 to deny palatine teeth to the genus Fsettus. The four species 



