174 BU. BASHFORD DEAX OX THE [Feb. 20, 



almost flat, its preaxial rim supporting the weight. In a third 

 position (fig. 3) the fish balances delicately on the tips of the fins ; 

 and here the weight of the anterior trunk is borne mainly on the 

 preaxial side of the pectoral fin ; the pelvic fins are extended 

 downward, barely touching the bottom, the preaxial margin 

 lowermost. In this position the fish sometimes remains for a long 

 time (30 minutes) ; and on one occasion it was observed to rock 

 slowly from side to side in a way which suggested strikingly the 

 well-known habit of Cryptohranchus. In this pose the axis of 

 the body is almost straight. In the following figure, however 

 (fig. 4), the axis is bent somewhat upward and the fish is slowly 

 moving forward ; the pectoral fins are flapping uj) and down in a 

 measured way accompanied by a marked rotation in the plane of 

 the fin, the pi-eaxial border first bending downward, and the 

 undulation here produced passes around the border of the entire 

 fin terminating a,t the axil : there is hardly perceptible a movement 

 of undulation of the entire body, and the pelvic fins lie closely 

 opposed to the wall of the trunk. A more active type of movement 

 is presented in figs. 5 and 6 : in the former the ti-unk undulates 

 and the paired fins express more active movements. The pectoral 

 is flapping downward and the figure gives an idea of its flexibility ; 

 the pelvic moving less widely ; its plane is vertical as it extends 

 from the side of the body and it attains a position almost trans- 

 verse to the axis of the body. In fig. 6 a somewhat similar 

 position is viewed slightly from above, and it shows particularly 

 the down-sweep of the paired fins : in the joectoral it will be seen 

 that the preaxial border is lowermost. In another position 

 (fig. 7) the undulating pectoral fin is seen somewhat in side view. 

 A rather interesting attitude is shown in fig. 8 ; here the fish, 

 after a period of rest, moves backward in preparing to change its 

 line of movement ; and it will be seen that the fish uses its paired 

 fins (IST.B. the functional elbow-joint) as an amphibian uses its legs 

 in pushing backward the weight of the body ; the down-bent 

 position of the head is also noteworthy. In figs. 9 and 10 the 

 position of the fish suggests again the amphibian. In fig, 9 the 

 weio-ht of the body is delicately balanced, the fish resting on its 

 fin-tips, its axis bent largely downward in a way strikingly unfish- 

 like. On one occasion, while in this position, it was observed that 

 a single pectoral moved as though the fish was about to " walk " 

 forward. In fig. 10 the fish has risen on the tips of its pectorals, 

 and these are greatly bent on account of the weight supported ; 

 the pel vies, spreading out forward and sideways, aid obviously 

 in supporting the fish. Fig. 11 depicts a characteristic position 

 of the swimming fish : the body is luidulating somewhat rapidly ; 

 the pelvics are closely apposed to the sides of the body, and the 

 pectorals are sweeping up and down with pendulum -like regularity. 

 In still more rapid movements the pectorals also become apposed 

 to the sides of the body and the propulsion is secured by vigorous 

 undulation of the entire body, reinforced by the sweep of the 

 eaudals. In fig. 12 the fish, after a period of swimming, becomes 



