608 DR, BASHFORD DEAN OlSI 



since it is fair to assume that they are living under fairly 

 normal conditions. In this connection it may be mentioned 

 that the fishes have been subjected to no changes in their 

 aquarial habitat ; indeed, they have remained practically undis- 

 turbed for over a decade. 



Among the notes dealing with these specimens are those of 

 the present writer, published six years ago in the ' Proceedings ' of 

 the Zoological Society of London (1906, vol. i. pp. 168-178), a con- 

 tribution which gave also data about Ceratodus summarized from 

 earlier literature. In this paper details were recorded regarding 

 the movements of the fishes, their mode of breathing, both with 

 gills and lungs, their manner of feeding, their nocturnal activity, 

 and in general their salamander-like habits. 



The writer had again the opportunity of observing these 

 specimens during June 1911 ; his supplemental notes are as 

 follows : — 



Golou7\ — One of the fishes, the larger one, remains notably 

 darker than the other. This distinction in colour, therefore, 

 is neither abnormal nor seasonal. Nor can there be vast adaptive 

 colour changes in Ceratodus, for the reaction to similar sur- 

 roundings would then be the same in the two fishes. Is the 

 darker specimen a male ? 



So far as could be learned, the fishes have shown no evidence 

 of sexual activity. The colours have lemained constant, and 

 there have been no signs of the brilliant tones noted by Schmeltz 

 (1876, J. Mus. Godeflr., vol. viii. p. 138). According to his 

 account, the ventral side of Ceratodus is of a deep orange-i-ed, 

 and sevei'al scales on the sides ai-e margined with red ; 

 nothing is aaid, however, of the relation of these colours to the 

 season. From the characters of the present specimens, and by 

 analogy with Amia, we can safely conclude that the tones of 

 orange and red appear only at the time of spawning. In Amia, 

 aqviarium-kept fishes show no bright colours, but under native 

 conditions the male fish develops wonderful brilliancy ; the spot 

 at the base of the tail is conspicuous, red scale-margins appear, 

 and the hinder abdomen glows with tones of orange. 



It was noted (1911) that the paired fins were margined with 

 a narrow white band. Could this have been an indication of 

 a breeding colour ? No coloration of this kind was seen on the 

 edges of the unpaired fins. 



Size. — At present the darker specimen measures 33^ inches, 

 the lighter 29| inches, having grown but a very few inches during 

 the past seven years. They have reached, accordingly, nearly 

 their greatest length, Macleay leading us to infer that 3 feet is 

 about their maximum (Cat. Austr. Fishes, p. 284). Exception- 

 ally, however, a specimen may measure 45 inches, such a case 

 having been cited by O'Connor (1897). 



Age. — The present specimens give us an idea of the age to which 

 Ceratodus may attain. We have in the first place data that they 

 have grown, broadly speaking, at the rate of three quarters of an 



