vi ENGYSTOMATINAE 231 



tuft, and dilating its throat, repeats its call ; but if in the least 

 disturbed, it is suddenly gone. The eggs are laid in quite tempo- 

 rary pools in grassy ground, and form separate globules of jelly, 

 which float on the surface of the water, and are heavily pigmented. 

 The development is excessively rapid. The segmentation be- 

 ginning at 10 A.M., they were hatched and wriggling about by 

 7 A.M. the following day. They are probably washed down into 

 deeper pools by the retreating waters, and for this purpose the 

 manner in which the eggs are laid, namely, in separate globules 

 of jelly, seems especially suited. 



Bracliycephalus ephippium in Brazil, the only species, is 

 remarkable for the development of a broad dorsal shield of bone, 

 which is fused with the processes of the second to seventh vertebrae, 

 an ossification which strongly resembles that of several species 

 of the likewise Brazilian Ceratophrys, a genus of the Cystignathinae. 



Stereocyclops is remarkable for the peculiar formation and 

 protection of the eyeballs. The anterior portion of the sclerotic 

 is ossified into a ring, which surrounds the transparent cornea. 

 Another peculiarity lies in the metasternum, which is so much 

 broadened out that its cartilage is in wide contact with the 

 posterior edge of the coracoids. The epidermis is everywhere 

 " thickened by a chitin-like deposit." The only species, S. incras- 

 satus, found near Eio Janeiro, is an altogether aberrant creature. 

 Its general appearance recalls that of Pipa. The gape is large, 

 with a slightly projecting muzzle ; the limbs are so short that 

 the upper arms and the thighs scarcely stand out from the 

 broadened and flattened body, which is leathery brown, with a 

 narrow white median line extending dorsally from the nose to 

 the vent. 



Engystoma, with about five species in the Southern States, 

 Central and South America, is the type-genus of the whole family, 

 chiefly on account of priority of name. It is fairly characteristic 

 in so far as the mouth forms a narrow, somewhat projecting snout ; 

 the precoracoids, the clavicles, and the omosternum are absent, 

 the palate is devoid of teeth, the lining of the mouth forms a 

 dermal ridge across the palate and another in front of the oeso- 

 phagus, the tympanum is hidden, the sacral diapophyses are 

 moderately dilated, and the tongue is elliptical and free behind. 

 The pupil is vertical. The fingers and toes are free, ending in 

 slightly dilated or blunt tips ; the terminal phalanges are simple 



