B.iTUACniA. 335 



froglike fashion on tlicir liaunclius, and were in all respects miniatures of the adult 

 spade-foots that in April and June made night hideous with their unearthlj' cries. 



" Having tested several s])ecimens, a few days previously, as to their ability to 

 assume the landdife of adult Scaphwpi, by placing them upon damp sand, and finding 

 that they throve fairly well, on the 25th of July I removed the water in the aquarium 

 and put in earth to about an inch in depth, and very carefully smoothed the surface, 

 l^pon this the young spade-foots were placed, and in less than one minute many had 

 commenced digging little burrows, into which they disappeared as the excavations 

 dee])ened. In all respects these burrows were like those made by adult spade-foots, 

 oval in outline, oblique in direction, and generallj' with the slight angle in the course. 



" In twentv minutes all but two, of forty-four specimens, were below the surface of 

 the earth stratum I had placed in the aquarium. 



" During this simple series of observations of young Sccqyhiopi in confinement, I 

 watched also the development of those left in the sink-hole. The water there soon 

 was confined to mere puddles concealed in the dead leaves, and before the young had 

 their limbs fully develojjed, the depth was nowhere sufficient to permit of swimming. 

 Three days in advance of the maturing of my confined specimens, I saw, in a sink- 

 hole, a few individuals which had fairly assumed the land-living, air-breathing stage of 

 existence. Supposing that, like those I had at home, they would burrow in the earth 

 where they were, I did not visit the locality from the 21st to the .31st of July, on 

 which date I made an exhaustive but unsuccessful search for them. Not a trace of 

 either young or adult could I discover. It cannot be said that they were overlooked. 

 My search was too careful and comprehensive for this, and I believe that these sjsade- 

 foots, both old and young, wander farther from their breeding grounds than is sup- 

 posed, or else dig far deeper into the earth than a depth of six or eight inches, as 

 stated by Holbrook and De Kay." 



The Hy'lid^, or true tree-toads, embrace one hundred and seventy-five species, of 

 which by far the greater number inhabit tropical America. About twenty species 

 inhabit Australasia, one species tropical Asia, and one, the Hi/la arborea, extends from 

 western Europe to Japan. The ball and claw-like character of the terminal jihalanges 

 of the toes of tlie members of this family have been already referred to. There are 

 dwellers in trees found in other families, especially in the Cystignathidic and the 

 Ranidas, all of which have flat or disc-like dilatations on the extremities of their toes, 

 like those of the Hylidaj. But the shape of the supporting phalange is different in 

 each case. In the IL/lodes type of Cystignathida; it is T-shaj)ed, and in the Ranidae it 

 is generally Y-shaped. In some members of the Hylida3 the characters are not very 

 well jiresented, especially in the North American genera Chorophilus and Acris, 

 which live on the ground, frequently in the neighborhood of water. Some of the 

 species of the typical genus Hyla have similar habits, and ajiproach those genera in 

 structure, viz., the Hyla jiickeriiKjii of North America. Among the arboreal tj'pos 

 there is a great range in the ossification of the skull, as I have already shown to be the 

 case in other families. In ILjpsiboas and Iltjla there is a large cranial fontanelle, 

 while in Trachycephalus the extensive cranial ossification occupies the skin, so 

 that the head is bared and rough on its upper surfaces. This forms an excel- 

 lent protection against snakes. In the genus Triprion this ossification is carried to a 

 great degree. It forms a prominent rim overhanging the mouth all round, jirojecting 

 m front like the brim of a cap in one species, the T. petasatus of Yucatan, or like 

 a spoon in anothei', T. .i2Jatulatus of West Mexico. This genus is also entirely 



