AMPHIBIA 273 



out living in any liquid except that of the egg. (P. G. Howes, Na- 

 ture Magazine, July, 1926, vol. 8, pp. 13-15.) 



A Cuban toad {Bufo empusus), called the shell-headed toad or, in 

 Spanish, sapo de concha^ lives in a burrow, and c^kz's, itself in, using 

 its hard horny head as an operculum. 



A gigantic frog {Rana goliath) , weighing ten pounds and said to be 

 " as large as a good sized terrier," is the largest frog known. It 

 comes from French West Africa where it is eaten by negroes who 

 " consider its thigh bones priceless for purposes of divination " 

 (Barbour). 



The smallest known frog {Phyllobates limbatus), one centimeter 

 long, was discovered in Cuba in 1910 by Thomas Barbour after 

 sixty years had elapsed from the time when the species was originally 

 described. 



Anura. Type — Leopard Frog (Rana pipiens).^ External Char- 

 acters. — The frog has no neck, its head being united to the trunk. 

 The eyes protrude considerably but can be withdrawn into the orbits 

 as the eye socket is not separated from the mouth by any of the bones 

 of the skull. In the center of the eye is a dark oval opening, the 

 pupil, which is surrounded by a brightly colored ring, the iris. 

 The eye is covered at times by the eyelids. The upper eyelid is 

 capable of but little movement, but the lower lid can be drawn up so 

 as to cover nearly the whole eye. The lower eyelid corresponds to 

 the lower eyelid of the mammal plus the nictitating membrane, 

 which appears to form a dorsal continuation of the lid. Behind the 

 eye is a nearly circular area, the tympanic membrane, the covering 

 of the drum of the ear. 



Above and behind the snout lie the paired nostrils or external 

 nares, guarded by valves which open and close in connection with 

 the respiratory movements. The tip of the upper jaw is movable 

 and when it is pushed upward the valves of the nostrils become closed 

 and prevent the passage of air. Inside the mouth are a pair of 

 openings, the internal nares. On the upper side of the head in 

 front of the eyes there occurs a small light-colored mark, the brow 

 spot, which is the outer portion of a glandular outgrowth of the 

 brain, the pineal gland. (See Hatteria, N. Z. Lizard, page 308.) 



The forelegs are short and consist of three divisions, the upper 

 arm, forearm and the hand. The hand has four fingers and an 



^The material herewith presented is largely compiled from Holmes, S. J., 1927, 

 Biology of the Frog, The Macmillan Co. 



