596 



MR. 6. A. BOtTLENGER ON THE 



[Nov. 17, 



fournis par la bouche des tetards des Batraciens anoures 

 d'Europe." Bull. Soc. Zool. France, 1881, p. 75. 

 M. H. Hinckley. " On some differences in the Mouth Structure 



of Tadpoles." Proc. Boston Soc. xsi. 1882, p. 307, pi. v. 

 3. The Spiraculum. — After the disappearance of the external gills, 

 the water is expelled from the branchial chambers by one or two 

 tubes opening hy one orifice in all European Batrachians\ In the 



Eis. 2. 



B A 



Lower -view of Tadpoles of, A, Hyla arhorea, J3, Alyfes ohstetricans. 



DiscoglossidcB two tubes are present, which converge towards the 

 mid-ventral line, where they discharge through one transverse, slit- 

 like or crescentic opening situated in the middle of the breast 

 (fig. 2, B, sp.). In all other tailless Batrachians the tube is single 

 and opens on the left side, straight backwards in Bufo, backwards 

 and upwards in the other genera (fig. 2, A, sp., fig. 3, A, B). The 

 first discovery of the median spiraculum appears to be due to 

 Pontallie (Ann. Sc. Nat. 3, xviii. 1852, p. 250), and to Lataste 



^ There are two openings, one on each side, in the Aglossa. 



