OCR Text |
Show 596 MR. G. A. BOULENGER ON THE [Nov. 17, fournis par la bouche des tetards des Batraciens anoures d'Europe." Bull. Soc. Zool. France, 1881, p. 75. M . H . H I N C K L E Y . " O n some differences in the Mouth Structure of Tadpoles." Proc. Boston Soc. xxi. 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 by one orifice in all European Batrachians1. In the Fig. 2. B A Lower view of Tadpoles of, A, Hyla arborea, B, Alytes obstetricans. Discoglossidce two tubes are present, which converge towards the mid-ventral line, where they discharge through one transverse, slitlike 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 1 There are two openings, one on each side, in the Aglossa. |