1906.] AUSTRALIAN LUNG-FISH. 169 



(Ramsay), cau be touched (Semon). Apt to rest for hours on the bottom, 

 pectoral fins extended at right ang-les to the body, pelvics parallel with it 

 (Kamsay). Neither diurnal, nor nocturnal, seeking food regai'dless as to 

 the hour of the day (Semon). 



Breathing. — Does not open gills Avhen out of water (Ramsay). Rises 

 to the surJ'ace to breathe every thirty or forty minutes (Semon), but more 

 frequently at night (Ramsay). Lung especially important when water 

 becomes muddy or foul (many authors). Sounds sometimes emitted, 

 ''■ spouting," a " groaning sound " (Semon), a " pig-like grunt " (lUidge). 



Swimming. — Progresses chiefly by " waves of the tail " or " by paddling 

 with pectoral fin alone." When disturbed "lashes out with its great 

 strong tail, aud turning sideways squeezes in between some tufts of grass." 

 "Eel-like in movements" — not apt to swim strfight fitrward; in this 

 event, however, pectorals are used, not caudals (Ramsay). "Swims a 

 short distance with a jerk, when it will rest again " (Semon). Its 

 movements are, however, best described by Semon, after notes made (1899) 

 upon the present specimens by Arthur Thomson : he distinguishes three 

 kinds of progression — (1) a slow forward movement in which the pectorals 

 play the most prominent part, waving "like a flag in a moderp.te breeze " ; 

 (2) a rising movement, accomplished almost exclusively by the pectorals, 

 after which the fish sinks slowly to the bottom Triton-like; and (3) a 

 rapid strong swimming, accomplished by the caudal, the pectorals and 

 ventrals being opposed to the side of the bottom, as in the case of rapidly 

 swimming amphibians. Thomson observed especially the fish in a 

 position of rest balancing: either on its ventromedian line, or partly lifted 

 up supported on its spread out pectorals, or further lifted or supported by 

 both pectorals and ventrals, the last position having been figured {cf. text- 

 lig. 53, 3, p. 173). This supporting function is particularly emphasised by 

 Semon as a step important functionally in the evolution of the land-living 

 vertebrate limb. Thomson, however, was unable to see the alternate 

 movements of the limbs, which had been described in Protoiyterus, or an 

 elbow-like bending of the base of the pectoral fin. 



Food. — Many authors emphasize its vegetivorous habits (Giinther, 

 Spencer) ; Semon, on the other hand, maintained that the food is 

 " essentiallv animal," the plant-material furnishes but a A^ehicle for the 

 animal food, and remains, therefore, undigested. Margo, finally, has 

 determined by njicroscopical examination that in cases where the plant 

 portion of the food-material is undigested in the anterior part of the gut, 

 in its hinder part there is convincing evidence of complete digestion, 

 leading to the conclusion that the diet of Ceratodus is a mixed one. 



Colour. — " Greenish brown on back, and slaty on belly " — after capture 

 " becomes very prettily coloured with red, pink, and violet hues on the 

 abdominal parts,"' colours which disappear after the death. The surface of 

 the fish is " oily " (lUidge). 



The present specimens — two in number, — as has ah^eady been 

 recorded (P. Z. S. 1898, p. 492), were secured in the Burnet River, 

 Queensland, during the beginning of 1898. They have accordingly 

 been kept in captivity for upwards of seven yeai-s *. Two other 

 specimens, however, which wei"e brought from Australia at the 

 same time and which passed into the possession of the aquarium 

 in Paris, lived, it is understood, but a short time. It is stated that 

 on one occasion during the transportation of these fishes suitable 

 tanks could not be procured and that the specimens were sent for a 



* During this interval they appear to have grown at the rate of a little more than 

 au inch a rear. 



