LACERTILIA IGUANIDAE EUPHRYNE OBESA. 561 



organic matter that remained entirely insoluble by treatment with a quan- 

 tity of boiling- water () received an addition of nitric acid, and was then 

 evaporated; the evaporated residue extracted with cold water, when a small 

 quantity of a yellow substance resulted that gave, with nitrate of silver and 

 acetate of copper, the precipitates characteristic of xanthine. The portion 

 undissolved was soluble in ammonia, and on evaporation of this sohition 

 there remained a yellow powder, little soluble in water. 



" These reactions, as well as the decomposition of the hydrochloric acid 

 solution of the organic matter on addition of water, show the presence of 

 guanine. The murexid reaction for uric acid was very feeble, and tyrosin 

 and leucin were searched for in vain. If the organic matter is treated with 

 cold, concentrated sulphuric acid, a dark, blood-red solution results, the 

 color of which is destroyed if water is added ; this and several other reac- 

 tions are very characteristic of bilious secretions. We have therefore, in 

 this case, a mixture of urinary excretion, bilious secretion, and feces ; and in 

 no animals except the Monotremata are these products united in the cloaca. 



"The question naturally arises: by what animals are these peculiar 

 deposits made ? always in the same spots, producing a continual increase of 

 the discharged masses into little mounds in localities where, unless furnished 

 with wings, small mammals could not climb ; as, for instance, the almost 

 vertical rock cliffs in Southern Utah. 



"At the first thought, the idea presents itself that it must be some winged 

 animal that is the cause, perhaps bats ; but considering the absence of any 

 signs of animal diet in the masses, and on comparing it with the excrement 

 of bats, this theory becomes untenable, and must be abandoned : not only 

 do the two substances differ in external appearance, but also in chemical 

 composition. The excrements of bats are full of the remains of insects, and 

 contain nothing soluble in water ; but we find nothing of the kind in the 

 substance under discussion. Moreover, there are no herbivorous bats in 

 North America so far known ; the existing species being natives of South 

 Africa and the East Indies. 



" Prof. S. F. Baird, assistant secretary of the Smithsonian Institution, to 

 whom these excreta have been shown, and the chemical examination com- 

 municated, supposes them to have been deposited by herbivorous lizards, of 

 36 z 



