ON Tllli; RSSPIllAroilV MOVEMCNTS OF NliCTITRUS. C)4i) 



35. Remarks on tlie liespirntory MovcMneiits ol jS\'cii(7visanil 

 Cryptohmnchus. By A. WiLi.KY, M.A., D.Sc, F.liS., 

 F.Z.S. 



[lleceived October 25, 1920 : Read Xovciulicn- 2, 1920.] 



In a foniier paper certain facts were pul)li,slied showing that, 

 under the conditions of observation, A^ecinrus, the " Mud Puppy " 

 or " Gilled Salamander," is normally a water-breather, not an 

 air-breatlier*. Shoi-tly afterwards I had the oppoi'tunity (May 

 24 and 25, 1918) of observing Necturns under the conditions 

 presented to it in the New York Ac|uarium, and of comparing its 

 behaviour witli that of the ''hellbender,'"' (fri/ptohraiichus 

 ^ = ]\fei)ojwma^. 



Between 11 am. and noon on May 24, after watching for ten 

 minutes, I saw one Cryptohranchvs yawn slowly to the full 

 extent of its gape under water at the bottom of the deep 

 aquaiium. Two others afterwards went through the same 

 performance, i. e. yawning under water. There were more than 

 a dozen individuals, all resting at the bottom of the aqunriuni 

 during my forty-minute vigil. One of them gave two rather 

 copior.sen)issions of air from the mouth, and a bubble was seen to 

 I'ise from the right gill-pore. None visited the surface. While 

 at the bottom they have a way of swaying gently hxm\ side to 

 side, whei-eby the longitudinal lateral cutaneous flap waves up 

 and down. 



At the same hour on the following day I found the hellbenders 

 actively engaged in ascending to the surface, remaining for some 

 miniites just below the suii'ace suspended in the water with 

 arched back, retaining that attitude whilst sinking to the bottom, 

 or else deliberately swimming to the bottom. They protruded 

 their muzzles above the surface without opening the mouth, a,n<l 

 in one case a deep inspiration tlirough the nostrils was effected by 

 the dilatation of the hyobranchial apparatus. The air thus taken 

 in may be expelled quickly from the mouth in a continuous 

 stream of bubbles, perhaps indicating that it had lieen used for 

 oropharyngeal respiration . 



Giant Salamanders (C. maximus), in a neighljoui^ing tank, 

 behaved like the hellbenders. On May 24 they were resting at 

 the bottom of the dee^i aquarium ; one of them emitted some air 

 through the mouth ; none visited the surface. But on the 

 following day they were restless, ascending to the surface. I saw 

 one of them, after pushing its muzzle above the surface, take a. 

 slow and deep inspiration through the nostrils by the dilatation, 

 to full capacity, of the hyobranchial apparatus. The latter 



* A. Willej' : " Brancliioderma and Brancliiotreraa." Trans. Ro^-. Soc. Canada 

 3rd ser. vol. xii. sect. iv. (May 1918), pp. 95-104. Ottawa, 1919. ' 



Proc. Zool. Soc— i920, No. XLIII. 43 



