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Show 1»" DR. BASHFORD DEAN ON THE [Feb. 20, similar movement is shown in fig. 13, the fish viewed 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 dark 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 fig. 17 a forward movement is again indicated ; but in this the undulation of the entire trunk is slowly functioning, and the pectorals are relatively inactive. In fig. 18 a position of rest is represented, which is not widely different from that shown in fig. 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 movements 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 paddles backward, closes its mouth, and commences 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 behaviour 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 salamandrine 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 movements as Protopterus, which will " walk " forward balancing itself on its paired fins. Of exceptional interest in Ceratodus, finally, are the movements of the neck and bend, which suggest strikingly those of Salamanders. References to the Habits of CERATODUS. 1901. BRUYfeRE. A.-" Le Ceratodus:' La Nature, An., 29 Sem. 2, pp. 89-91, fig. 1. 1884. C A L D W E L L , W . W.-(Ref. to living Ceratodus.) Journ. & Proc. Royal Soc. N.S.W. vol. xviii., & Phil. Trans. R. S. vol. clxxviii. |