ON TtlE RESPIRATORY MOVEMENTS OF NECTURUS. 



G49 



35. Remarks on the Respiratory Movements oE JS^ect urns and 

 Cryptohranclais. By A. WiLLEY, M.A., D.Sc, F.li.S., 

 F.Z.S. 



[Received October 25, 1920 : Read Novenil)er 2, 1920.] 



Id a former paper certain facts were publislied showing that, 

 nnder the conditions of ol)servation, jSectarus, the " Mnd Pnppy " 

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

 air-breather*. Shortly afterwards I had the opportnnity (May 

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

 presented to it in the New York Aquarium, and of comparing its 

 behaviour with tliat of the liellliender,"' CryptohrancJius 

 ^ — Menopoma\ 



Between 11 a m, and noon on May 24, after watchiug for ten 

 minutes, I saw one Cryptohrcmclms yawn slowly to the full 

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

 aquarium. Two others afterwards went through the same 

 performance, i. e. yawning under water. There wei-e more than 

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

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

 copior.s emissions of air from the mouth, and a bubble was seen to 

 i-ise from the right gill-pore. Noue visited the surface. While 

 at the bottom they have a. way of swaying gently from side to 

 side, whereby the longitudinal lateral cutaneous flap waves up 

 and down. 



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

 actively engaged in ascending to the surface, lemaining for some 

 minntes just below the surface suspended in the water with 

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

 or else deliberatel}^ swimming to the bottom. They protruded 

 their muzzles above the surface without opening the mouth, and 

 in one case a deep inspiration through the nostrils w^ns 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 been used for 

 oropharyngeal respiration . 



Giant Salamandei'S {C. maximiis), in a neiglibouring tank, 

 ])ehaved like the hellbenders. On May 24 they were resting at 

 the bottom of the deep 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. Willey : " Brancliiodenna and Brancliiotreraa." Trans. RoJ^ Hoc. Canada, 

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



Proc. Zool. Soc— 1920, No. XLIII. 43 



