248 SUMMARY OF CURRENT RESEARCHES RELATING TO 



organ is simple ; in double-smellers the olfactory organ is complex and 

 Jacobson's organ is present. Thus Seydel's view is confirmed, that the 

 organ of Jacobson is used primarily to test the contents of the oral 

 cavity. 



Respiratory System of Thyphlonectes.*— 0. Fuhrmann has studied 

 the extraordinary peculiarities of the respiratory system in this Ca3cilian. 

 In other Gymnophioua the left lung is very rudimentary and the right 

 lung reaches to about the posterior third of the liver (exceeding the 

 liver a little in Ghthonerpeton). In Thyphlonectes the right lung reaches 

 to near the cloaca and the left lung reaches well below the liver. Both 

 are very narrow and show all along their length cartilaginous rings, like 

 the trachea, sometimes with a slight trace of ossification. The right 

 lung has about 180 of these. This is quite unique. The long trachea 

 gives off ventrally in front of the heart a peculiar spindle-shaped en- 

 largement, which turns out to be an accessory third lung. There is also 

 cutaneous respiration and probably buccal respiration. The animals 

 often swim actively in pursuit of fishes, and the narrow lungs evidently 

 require to be assisted. 



Peculiar Air-sac in a Lemur. f — R. Anthony and I. Bortnowsky 

 describe in Microcebus from Madagascar a very interesting subcutaneous 

 cavity, lined with stratified epithelium, which extends along the dorsal 

 surface to the bases of the limbs. It appears to be in connexion with the 

 air-passages, probably opening into the trachea behind the larynx, like the 

 retro-tracheal sac of some other Lemuroids, but this point has not been 

 cleared up. It is suggested that the sac has to do with equilibration. 



Poison-glands of Snakes.} — Marie Phisalix finds that the dif- 

 ferences in the poison apparatus in different kinds of snakes cannot be 

 used for taxonomic purposes. The elaborateness of the apparatus as a 

 whole is not correlated with the toxicity of the poison. The poisoning 

 function has been superposed on the older function of salivary digestion, 

 and a salivary toxicity is observed in other types. The poisonous quality 

 is an exaggeration of a more general disintegrating and digestive 

 action. 



Modifications in Birds due to Changes of Diet.§ — A. Magnan has 

 made an interesting series of experiments on the mechanical and chemical 

 effects of different diets on young ducks belonging to the same brood. 

 The different diets were insects, fish, flesh, and vegetables, and the 

 naturally omnivorous ducks were able to live normally on any one of 

 these. These experiments showed that a vegetable diet considerably 

 increases the surface of the digestive tube, while a carnivorous diet 

 reduces it. The casca and the large intestine vary in the same manner, 

 being most developed with a vegetable diet. The weight of the intestine 

 is greater in animals which subsist on rigid prey, because of the 



* Zool. Anzeig., xlii. (1913) pp. 229-34 (7 figs.). 



t Arch. Zool. Exper., liii. (1914) pp. 309-24 (2 pis. and 7 figs.). 



% Ann. Sci. Nat. (Zool.) xix. (1914) pp. 65-104 (5 pis.). 



§ Ann. Sci. Nat. (Zool.) xix. (1914) pp. 115-225 (32 figs, and tables). 



