382 DE. GUNTHEE 0\ THE FISHES OF CENTEAL AMEEICA. 



fauna species which may be expected to belong to it, although they are not yet disco- 

 vered within its limits, I have excluded all species not actually known from Guatemala, 

 although they have been obtained north and south of it. A collection made by Mr. 

 Godman at Belize was of great value in determining this part of the fauna. 



Numerous species of fishes have been described from Mexico' ; and if we were better 

 acfiuainted wdth their geographical distribution, it would have been useful to treat at 

 least of the southern portion of them, in conjunction with the Guatemalan species. 

 Unfortunately but a small proportion of tlie exact localities are known, so that at 

 present no line can be drawn to indicate where the preponderance of nearctic types 

 over tropical ones terminates. Thus, confining myself to the fishes occurring between 

 the political boundary of Guatemala in the nortli and the Isthmus of Darien in the 

 south, I would repeat that, previously to the receipt of the collections forming the basis 

 to this Memoir, only a small number had been described, as will be seen from the 

 following remarks : — 



(^S 4. Historical account cjf Publications previous to this Memoir. 



It would be of but little advantage to enumerate the few isolated species incidentally 

 described in general works or memoirs as occurring in Guatemala or Panama. How- 

 ever, I must mention that the first traveller who collected fishes in these states appears 

 to have been Baron von Friedrichsthal. I am not aware that any account of his 

 travels has been published ; but in a paper published by the late Jacob Heckel in 

 'Annalen des Wiener Museums,' vol. ii. 1840, a single species is described, which is 

 stated to be from Friedrichsthal's Central-American Collection, and which I have 

 recognized as belonging to the Lake-Peten fauna {Ileros friedrichsthalii). The greater 

 part of the collection made by this gentleman evidently remained unpublished until 

 1864, when Dr. F. Steixdachner determined from it four other species (Denkschr. 

 ^Akad. Wiss. Wien, xxiii.), viz. : — Hcros urophthcdmus (Gthr.), Heros triagrawimi--H. 

 salmm{Gt\iv.), Heros melanopogon, and Fctenia splendida (Gthr.). As we have received 

 four of these species from Lake Peten, it is very probable that Baion Friedrichsthal 

 visited and collected in that locality. 



In the second place I have to mentioirD*', Sekmann, who, as naturalist attached to 

 the expedition of the ' Herald,' brought to England a collection of Central-American 

 fishes. These, as I have mentioned above, were originally deposited in the collection of 

 Haslar Hospital, but no record as regards the origin of the specimens was kept, so 

 that most of them are lost for the purposes of this Memoir. 



In the year 18G1 I received the first collections from Mr. Salvin and Capt. Dow. 

 Tlie species belonging to the families treated of in the 3rd volume of the ' Catalogue of 

 Fishes ' were described therein ; and a separate account of those sent by the latter 



' Prof. Troschel enumerates some 130 frcsliwuter and marine species in Miiller's ' Eeisen in den Yereinigten 

 Staaten," &c. 



