UlSToMKiY OK THK 1'01SO\-<;],.\\1>S OK Hl'KO AGUA. 



GENERAL. 



Bufn ayua 1 (horrifliix, nutciiliivtitrix, imirinuN, liumcnilix. aniiiliix, ic/iricux, Inzurux. l\nini 

 intiritifi, Hunibinator Imrridus, Neotcs, Pscinliiliiifn, and Docidopliri/ni' fiyua), on which tlic>c 

 studies were made, is a huge tropical toad inhabiting sonic of the \Yest Indies, Sotitli and 

 Central America, and part of Mexico. It is the largest of the . \nura, measuring alioiil 

 11.5 cm. from nose-tip to the end of the urostyle and having a maximum breadth of 4..~> cm. 

 when not inflated. The toad exhibits on the back and sides large numbers of warts or 

 buried masses of subcutaneous glands which reach their maximum development along Hu- 

 mid-dorsal region. The dorsal surface of the limbs and the upper eyelid are also warty. 

 the protuberances on the hind limbs being much more prominent than those of the anterior 

 extremities. These warts have been shown to result from the collection, beneath the 

 epidermis, of masses of cutaneous glands, which, lying as they do over a comparatively 

 unimpressionable substratum of bone, muscle, tendon, and cartilage, cause in the compara- 

 tively loose skin the swellings and depressions which give it its general unevenness of contour. 



The skin of the toad is a deep muddy brown color on the dorsum, with an underlying 

 reddish tone over the snout, jaws, and parotid region. There are no definite blotches of 

 pigmentation, but the warts and bony prominences have a lighter color than the level skin 

 about them. In general, the ventral surface is very light gray or white, the color-change 

 from the brown of the dorsal skin occurring along a line made by the junction of the ventral 

 and lateral surfaces of the animal when it is squatting on the ground. The coloring of the 

 toad follows the general rules of protective coloring for animals of its species and harmonizes 

 with its usual earthy backgrounds when viewed from above. On the ventral surface only 

 a few very tiny warts are visible to the naked eye beneath the jaw, but the ventral skin 

 seems marked out into areas like paving-blocks by small, fine wrinkles. The ventral surface 

 is mottled all over with irregular patches of gray-brown pigment which are largest between 

 the limbs and which become confluent near the junction of the belly with the lateral surface 

 of the animal, forming a zone of solid gray-brown. The ventral surfaces of the hands and 

 feet, which are chocolate brown in color, show numerous reddish warts which may reach 

 0.5 cm. in diameter. 



By far the most noticeable of the projections on the animal's body are the huge warty 

 masses formed by the acini of the "parotid" (figs. 1, 2, and 3) poison-glands. These large 

 warts, which are roughly oval in shape, begin just behind the eye and, surrounding the upper 

 bordei of the tympanum, pass backward and outward well down over the shoulders. The 

 skin over these glands is somewhat lighter in color than that covering the surrounding 

 tissues and shows, even to the naked eye, the numerous pinhole-like openings of the indi- 

 vidual gland-ducts (fig. 1). From these ducts, if pressure be applied over them, or if the 

 animal be sufficiently stimulated electrically or by other means, an abundant thick milky 

 secretion spurts, which is extremely poisonous to animals with whose mucous membranes 

 it comes in contact. The position and prominence of these "parotids," long known as 

 poison-glands, make them very effective for the service which nature intended they should 

 render. Thus, when the toad is seized in the mouth of an animal which would prey upon it, 

 the contents of the poison-glands flow freely on to the animal's oral mucous membram-. 

 The effect of such a charge of venom is almost immediate and the discomfort induced 

 by its exhibition insures the prompt release of the toad. 



'The name ttiifn IKJUU \v:is usnl l>y Alx-1 anil Maeht in their tleseriptinn of the tilaml sei-retion ami, in order In idrnlily 

 these hislolojiieal <( in lies wilh I In- iiliysioliiuieul HIM-- preeediim them, we will tlinniulinlll I hi* |I:I|IIT llsi- I In- same name \\ it In ii 1 1 

 rcganl for zoological fitness. 



