Spencer— Zhe Blood Vessels of Ceratodus. 3 
Lumbholtz’s informant must have mistaken a large water-lizard (Physzgnathus lesueurit) 
which is frequently met with in the Burnett for a Ceratodus. The former animal 
constantly climbs out on to logs and suns itself and may grow to a large enough size 
to be mistaken for a Ceratodus. It is dark-coloured like the logs and rapidly slips 
off into the water when disturbed. Dr. Giinther refers to statements as to the 
animal going on to land, or at least mud-flats, but regards these as doubtfully true. 
In discrediting them he was, I believe, after watching the animal in its native haunts, 
perfectly correct and this for two reasons—first, because the animal cannot move on 
land; it does not when taken from the water even throw itself about in the lively 
way of ordinary fish and never attempts to raise itself by its weak paddles; and 
second, because out of the water, unless kept moist artificially, its life is limited to a 
comparatively short time. 
The noise made by Ceratodus, and to which Dr. Giinther refers, is due probably 
to the expiration of air from the nostrils just as the animal reaches the surface, the 
result being what the fishermen of the district call a “ spouting.” 
Whatever be the state of the water, the animal appears to constantly breathe 
air; but there are two special times when its lung is probably of greatest use to it. 
The first of these is when the river is flooded by the yearly rains and the water is 
charged with an immense amount of fine sandy particles washed down from the 
surrounding country. The Burnett runs in a deep channel with every now and then 
great sandbanks—bare in dry weather and extending for long distances. The 
quantity washed down into the river during often a very few hours must be 
enormous. The second is when the river is abnormally low during the hot season 
and when its waters become fouled with gases from decomposing vegetable matter— 
for as the hot season advances the river weeds increase very rapidly in quantity. 
During either of these times it is easy to see that the possession of a lung to an 
animal which could remain in its normal element would be of great service. 
The development of the swimming bladder of ordinary fishes into the lung of 
Dipnoi has been attended with certain important changes in the circulatory system 
and we find that the latter presents, as might have been expected, remarkable points 
of affinity to not only the arterial but also the venous system of Amphibia. 
So far as I am aware, our knowledge of the blood-vessels of Ceratodus is as yet 
comparatively small. I have been unable, owing to lack of literature in Melbourne, 
to ascertain exactly what is already known. To my friend Professor Haswell of 
Sydney University I am much indebted for a copy of the part of Boas’* paper 
referring to Ceratodus, though, unfortunately, in the paper from which Professor 
* Ueber Herz und Arterienbogen bei Ceratodus und Protopterus. Von J. E. V. Boas. Morph. Jahrbuch, VI. 
pp. 331-354. 
