650 



DR. A. WILLEY ON THE llESPIRATORY 



bulges conspicuously downwards and backwards so that the 

 greatest convexity lies behind, at the base of the throat. 

 Presumably, in this act of dilation, the glottis is opened ; and, in 

 fact, CryptohrancJms seems to show some increase of girth after 

 inhalation. 



Inhalation through the nostrils was observed by G. B. Wilder 

 in a Japanese CryptohrancJms, 2| feet long, which he kept in 

 shallow water sufficient to cover it *. The downward protrusion 

 of the floor of the mouth in narial inspiration, the arching of the 

 back, and the swaying movement at the bottom have been 

 described by A. M. JR-eese t, who adds that the hellbender wdll 

 survive more than a week's exposure out of water without 

 suffering any permanent diminution of vitality. The longest time 

 that any individual was observed by him to remain under water 

 was 43 minutes. B. G. Smith t confirmed the observation that 

 the arching of the back is a sign that air has entered the lungs. 

 No w^riter seems to have reported the extraordinary yawning 

 under water to which I have alluded. 



Anotlier equally deep tank held at least a dozen examples of 

 Xecturus. On both occasions they remained undisturbed at the 

 bottom of the aquarium without betraying any signs of unusual 

 activity such as would attend recent or approaching visits to the 

 surface. Some of them had lived for three years in the aquarium ; 

 their bodies were sleek, firmly rounded, and fully extended. 



There is a point concerning the vascvdar system which requires 

 slisht emendation. All tiie blood that leaves the heart of 

 Necturus passes through the afferent branchial arteries to the 

 external gills. J. E.^Y. Boas (Morph. Jahrb. vii. 1882) had 

 described an external carotid artery arising from the first afferent 

 artery on each side, between the heart and the base of the first 

 gill. I have satisfied myself by injection that this artery does 

 not exist in the position claimed for it by Boas. It arises from 

 the first efferent artery as described and figured by W. S. Miller §. 



Unfortunately, two papers by H. L. Bruner had escaped my 

 notice earlier \\. In these regular oscillations cf the floor of the 

 mouth in aquatic respiration are attributed to Necturus, and, 

 under certain experimental conditions, of which temperature is 

 one of the factors, pulmonary respiration is stated to occur at in- 

 tervals. Bruner's analysis of the respiratory movements observed 



* Burt G. Wilder : "On the habits of Cryptohranclius.'" Amer.Nat. xvi. pp. 816- 

 817, 1882. 



t Albert M. Reese: "The habits of the Giant Salamander." Pop. Science 

 Monthly, vol. Ixii. pp. 526-531. New Yorlc, 1903. 



"1; Uertrain G. Smith : "The life-history and habits of Cn/ptohrancJnts aUeglieni- 

 ensisr l?iol. Bull. xiii. pp. 5-39, 1907. 



§ W. S. Miller : " The vascular system of Necturus inacnlafns.'" Contributions 

 from the Anatomical Laboratory of the University of Wisconsin, Bull. Univ. 

 Wisconsin, No. 33, Science Series, vol. ii. No. 3, pp. 211-226, pis. ix.-xi. Madison, 

 Wisconsin, 1900. 



II H. L. Bruner: 1. "The Mechanism of Pulmonary Respiration in Amphibians 

 with Gill-Clefts." Movph. Jahrb. xlviii. pp. 63-82, 1914. 2. " Jacobson's Organ and 

 the Respiratory Mechanism of Amphibians/' Ibid. pp. 157-165. 



