ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 661 



and Kohn's are apparent rather than real, and chiefly due to differences 

 in terminology. While the medulla of the suprarenal in mammals is, 

 as he believes, in origin derived from the sympathetic as in other 

 Vertebrates, yet in the adult it seems to be no longer nervous but 

 glandular, producing a characteristic internal secretion. The cortex 

 of the suprarenal the author regards as corresponding to the intcrrenal 

 of Elasmobranchs. Believing therefore that the above position is con- 

 firmed on all sides by different forms of evidence, the author is wholly 

 nnablo to accept Aichel's * views that both medulla and cortex originate 

 from the nephrostomes of the mesonephros, and that the medulla has 

 nothing to do with the sympathetic. He points out especially that 

 Aichel says nothing of the remarkable secretion, so characteristic of the 

 paired suprarenals of Elasmobranchs and of the medulla of the supra- 

 renals in Mammals, or of the comparative morphology of the supra- 

 renal throughout the Vertebrate phylum, and believes that Aichel's 

 results emphasise the danger of relying exclusively on embryological 

 work in studying such a problem. 



Japanese Dancing Mice.f — E. von Cyon notes that in these crea- 

 tures, which move only sideward?, never forward or backward, only one 

 of the three semicircular canals is developed. The mice can hear notes 

 about the pitch of their own squeak. If their eyes are bandaged, 

 equilibrating movements are disturbed. On a turntable they stop their 



dance-like movements and remain at rest. 



i 



Nostrils of Aquatic Snakes.} — Dr. Eudwig Kathariner notes that 

 among the peculiarities of those snakes which habitually live in water, 

 the presence of valved nostrils is usually numbered, the inference being 

 that the nasal openings are closed by muscular action. He finds that 

 this is not the case in any aquatic snake, for the nostrils invariably 

 close automatically under water, and are opened by muscular action 

 during breathing. The closing action is effected by means of cavernous 

 tissue, which is compressed by muscular action during breathing. In 

 order to allow room for the closing apparatus, the outer nasal chamber 

 (Nasenvorhof), which is virtually absent in other snakes, is not only 

 present, but may (Chersydras and Hydrophidaa) reach a great length. 

 The nasal gland is generally present in aquatic snakes, but is absent in 

 Pelamis bicolor, and the olfactory epithelium diminishes in superficial 

 extent as the adaptation to the aquatic life increases. The nasal muscle 

 is absent in Hydrophidse and Chcrsydrus, although, except in Pelamis, 

 the nasal gland is present. Jacobson's organ was found to be well 

 developed in all the snakes studied. 



Variation in Frog. § — Dr. Earnest Warren notes that three times 

 in three years he has noticed in frogs used for class-dissection the 

 occurrence of a vessel passing from the lung to the hepatic portal 

 system. In the last case observed an artery and a vein ran side by side. 

 The artery arose from the posterior mesenteric artery, and passed to 

 the apex of the lung, while the corresponding vein bifurcated, one 



* Cf. this Journal, ante, p. 561. 



t Arch. Ges. Physiol., lxxix. (1900) pp. 211-302. See Zool. Centralbl.. vii. (1900) 

 p. 705. % Zool. Jahrb. (Abt. Syst.), xiii. (1900) pp. 415-42 (2 pie. and 4 fiqs.). 

 § Anat. Anzeier., xviii. (1900) pp. 122-3 (1 fig.). 



