xiv PREFACE. 



BATRACHIA. Ouly four species of Frogs were collected in the 

 interior, namely, Phryniscus IcBvis, Gthr. ; Hylodes unistrigatiis, Gthr. ; 

 //. Whymperi, Bouleng. ; and Nototrema marswpiatum (Dum. & BiJDr.). 

 Of these, the first mentioned is I think the most widely distributed, 

 and the last named is the most numerous. In the vicinity of the town 

 of Machachi we saw thousands, and must have heard hundreds of 

 thousands of frogs,^ principally of this latter species, — which is very 

 variable in its colouring and markings. Of the Hylodes it may be 

 remarked that we obtained all our specimens upon the ground. The 

 species with which Mr. Boulenger has associated my name was observed 

 only at rather highly-placed localities, and seems very restricted in its 

 range in altitude ; whereas Phryniscus Icevis is seen at almost every 

 height between 7000-13,500 feet. 



PISCES. The readers of Humboldt's works will remember the 

 remarkable statements which were made by him about the little silu- 

 roid fish which he described and figured as Pimelodus cyclopum.^ I 

 should scarcely have been led to make any search or enquiry for this 

 fish if I had not seen the remarks by Dr. Putnam in the American 

 Naturalist, 1871, p. 694, and learnt that Humboldt's fish appeared to 

 have been described upon five or six diff"erent occasions, under as many 

 different names. Dr. Putnam advanced the opinion that the whole of 

 these so-called diff"erent species should be referred to one, somewhat vari- 

 able, species. The descriptions were based either upon single specimens, 

 or upon a very small number of examples, and I thought it advisable 

 to procure a considerable number, from different localities, so that the 

 whole subject might be re-investigated. Several hundreds were procured 

 on the spot ; these were reduced to fifty-one, and I had the advantage 

 of submitting them, upon my return, to the independent examination of 

 Dr. F. Day, who coincides with the views expressed by Dr. Putnam.'^ 



^ Compare this with Orton ; "of frogs there are not enough to get np a choir." 

 'The Andes and the Amazons, English ed., p. 107. 



^ Observations de Zoologie et d' Anatomic comparee, vol. i. pp. 21-5, \A. 7, Paris, 1811 ; 

 and in Aspects of Nature, vol. ii. p. 34. 



^ Some remarks upon this fish will be found in my Chapter upon Cayauibe. 



