17() DR. BASHFORD DEAN ox THE [Feb. 20, 



similar movement is shown in fig. 13, the fish Auevved from above. 

 In fig. 14 is shown a rather unsuccessful attempt to depict the 

 fish in resting position, viewed from the side and behind, and in 

 the three following figures are shown sketches of the fish made from 

 in front. In fig. 15 the slowly flapping pectorals are shown in a 

 somewhat rare position, paddling alternately : in this position, by 

 the way, one notes the almost closed mouth and the dai"k openings 

 of the nostrils just within the rim of the upper lip, through which 

 the major supply of water is passing to the gills. In fig. 16 the 

 fish is represented in somewhat the same position as shown in 

 lateral view in fig. 9 : the preaxial border of the fin is turned 

 inward, and in this sketch the opercular flaps appear well distended. 

 In fio'. 17 a f oi-ward movement is again indicated ; but in this the 

 undulation of the entire trunk is slowdy functioning, and the 

 pectorals are relatively inactive. In fig. 18 a position of rest is 

 represented, which is not widely difliei-ent from that shown in 

 fin-. 3 : in this case, however, the pectoral fins do not quite touch 

 the bottom ; the head, however, will shortly sink and the fish 

 assume the position shown in fig. 3. 



In text-fig. 55 the attempt is made to indicate the move- 

 ments of the fish in the process of coming to the surface to 

 breathe. In fig. 19 it swims slowly to the surface, the paired fins 

 flapping lazily. In fig. 20 a similar position is shown. In fig. 21 

 the head is shown thrust vigorously above the surface, the mouth 

 widely open in the process of filling the opercular cavity with air. 

 In fig. 22 the fish pp.ddles backward, closes its mouth, and com- 

 mences to contract the opercula. In this process, during which 

 evidently the air is pressed into the lung, bubbles escape through 

 the imperfectly closed opercular slits on either side, and sometimes 

 also through the closing mouth. 



The belmviour of Ceratodus, in conclusion, is decidedly like that 

 of an amphibian. In the first place, it breathes largely through 

 its nostrils ; in the second place, it is salamaudrine in its movements. 

 Not only does it support itself on its fins, as Arthur Thomson 

 observed, but it is able to push itself backward, in this operation 

 indicating that an elbow-like joint is functional. It has also been 

 observed to paddle forward, using alternate movements of the 

 pectoral fins. It is not, however, so amphibian-like in its move- 

 ments as Frotopterus, which will " walk" forward balancing itself 

 on its paired fins. Of exceptional interest in Ceratodus, finally, 

 are the movements of the neck and head, which suggest strikingly 

 those of Salamanders. 



References to the Habits of Ceratodus. 

 aE. A. — " Le Ceratodus." La Nature, A 



pp. Ot7-91, fig. 1. 



1884. Caldwell, W. W. — (Ref. to living Ceratodus.) Journ. & 

 Proc. Royal Soc. N.S.W. vol. xviii., & Phil. Trans. R. S. 



1901. Bruyere. a. — " Le Ceratodus." La Nature, An., 29 Sem. 2, 

 pp. 89-91, fig. 1. 



vol. clxxviii. 



