660 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



Hermaphroditism in Frog".*— S. J. Ognew describes a case in Rana 

 temporaries, and provides a summary of previously recorded cases with 

 brief particulars regarding each. Apparently there is some' relation 

 between the sex-gland and duct in most cases. For example, on the side 

 where the testis is developed, the oviduct is poorly so ; where the oviduct 

 is well developed the testis is slight, while the ovary scarcely reaches the 

 normal size. 



Lymphatic System of Frog Larva.t — H. Hoyer, jun., gives a 

 clear account of the distribution of the lymph vessels in tadpoles of 

 Rana temporaria, which is well illustrated in the figures accompanying 

 the paper. The origin of this system is paired and the distribution 

 is symmetrical ; as far as known this appears to be the case in all 

 Vertebrates. 



Anatomy of Giant Salamander.^ — Albert M. Reese gives a full 

 account of the skeleton and vascular system of C'ryptobranchm alle- 

 gheniensis. 



Life-history of Cave Salamander. § — Arthur M. Banta and Waldo 

 L. McAtee have made a study of Sperhrpes maculicaudus (Cope) from 

 Carolinian caves. The larva? are hatched and develop in the deeper 

 fastnesses. After, and even before, transformation there is a gradual 

 movement towards the mouth, where the adults are most numerous. The 

 adults climb well, helped by-their prehensile tails. When disturbed they 

 can leap a foot or more at the first move. The eye is in nowise 

 degenerate. Mating has not been observed, and the eggs have not been 

 seen. The metamorphosis of the larvae is described, and the develop- 

 ment of the colour pattern. 



Galvanotropism of Fishes.|| — J. Breuer has made numerous experi- 

 ments, showing, for instance, that a galvanic current transverse to the 

 head affects fishes (Gobio JiuviatiUs) in such a way that the head turns 

 towards the anode, while trunk and tail form a concave curve towards 

 the anode side. The trunk and tail show a similar curvature when the 

 influence of the head is eliminated. The phenomenon depends on the 

 direct excitation of the ganglion-cells of the spinal cord. Breuer com- 

 pares what he has observed in fishes with the galvanotropism of warm- 

 blooded animals, where the influence of the labyrinth is more marked. 



Mechanism of Air-bladder in Fishes.f — 0. Thilo has experimented 

 with carp with a view to discovering the source of the gas within the 

 bladder. He is of opinion that it enters by the air duct, because when 

 the bladder is emptied in an air-pump, in five hours it is again filled. On 

 account of the small amount of blood in the fish and the sparse blood 

 supply of the bladder, it is highly improbable that the blood is the 

 source. Further, nitrogen is present in quantities varying from 

 60-80 p.c. In the blood there is only a trace of this gas. This of 



* Anat. Anzeig., xxix. (1906) pp. 194-203 (1 fig.). 



t Op. cit., xxvii., Erganzungsheft, 1905, pp. 50-62 (3 figs.). 



j Amer. Nat., xl. (1906) pp. 287-326 (14 figs.). 



§ Proc. U.S. Nat. Mus., xxx. (1906) pp. 67-83 (3 pis. and 3 figs.). 



II SB. Akad. Wiss. Wien, cxiv. (1905) pp. 27-56. 



f Zool. Anzeig., xxx. (1906) pp. 591-604 (3 figs.). 



