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Show 1890.] MR. O. THOMAS ON MAMMALS FROM VERA CRUZ. 71 the egg, the fish-like larva does not acquire any external gills, opercular folds are distinctly visible and water taken in by the mouth is expelled by these branchial clefts. On the third day, the head broadens, flattens ; the eyes become large and prominent; the nostrils assume a dorsal position; the gape of the mouth increases in width and two long maxillary barbels rapidly appear near the angles of the mouth, and soon grow into long feelers which give the advanced larva its well-known Siluroid appearance. Neither in the embryo nor in the tadpole are any teeth or horny plates developed in the jaws; nor are there any special papillae surrounding the mouth. I have prepared and forwarded some ova and early larvae to Dr. Schauinsland, of Bremen, who proposes to investigate the development. Xenopus Icevis, unlike most frogs and toads, does not produce any croaking, but has during the breeding-season a peculiar dull tick-tick note, almost inaudible at three feet distance, which it produces under water. I have satisfied myself, by dissections, that the sound is produced by friction of the glottis against the borders of the (median) eustachian opening, the air being at the same time carried from the lungs into the buccal cavity, and vice versd1. 5. O n a Collection of M a m m a l s from Central Vera Cruz, Mexico. By O L D F I E L D T H O M A S , F.Z.S., Natural History Museum. [Eeceived January 14, 1890.] (Plates VI. & VII.) During the years 1887 and 1888 a large number of zoological specimens were collected in the Province of Vera Cruz by a scientific expedition organized by the authorities of the Mexican Museum, under the superintendence of Dr. F. Ferrari Perez, Director of that Institution. Thanks to the kind intervention of Messrs. F. D. Godman and O. Salvin the Mammals then obtained have been entrusted to m e for determination, and a duplicate set of them acquired by exchange for the Natural History Museum. The collection consists of about 100 mammals, belonging to 21 species, and a complete list of them is given below. The importance of this series lies in the fact that every specimen has been properly labelled with its exact locality and date, and in many instances with its native name and the colour of its eyes, all of these particulars being too commonly neglected in the case of mammals by the very collectors who would insert them most carefully on the labels of birds. 1 [Six examples of Xenopus Icevis have just been received alive by the Society from their excellent correspondent the Bev. Gr. H. E . Fisk. They were obtained at Eondebosch, near Capetown.-P. L. S.] |