On the Eremophihis and Astrollepus. 329 



• The sulphuretted oxide of manganese thus forms an ex- 

 ception to the rule hitherto observed, if we do not admit 

 hvdrogen into this substance as one of its constituent 

 parts. 



LIX. Memoir on the Eremnph'ilus and Asirohleput , two new 

 Genera of the Order of Apodes. By M. De Humboldt *. 



\y HEN we ascend the chain of the Andes to the height 

 of 2600 toises (l666lf Enghsh feet) and upwards, great 

 level plains and lakes of a considerable extent are seen. It 

 is singular to observe, that, while the soil is still covered 

 with a beautiful vegetation, the woods filled with quadru- 

 peds, and the air with a great variety of birds, the water 

 alone, the lakes and the rivers, are so little inhabited. The 

 cause of this phaenomenon relates, without doubt, to geo- 

 logical facts ; it pertains to the grand mystery of the origin 

 and migration of species. 



The considerable lakes which surround the city of Mex- 

 ico, at the height of 1160 toises fj nourish but two species 

 of fish, of which one, the axalotl, belongs rather to the 

 genera sirenns and proteiis. M. Cuvier, to whom we brought 

 this extraordinarily organized animal, unknown in Europe, 

 is engaged with its anatomy, which he will shortly publish. 

 In the kingdom of New Granada, in the beautiful valley of 

 Bogota, about 1347 toises high, there also exist but two 

 species, which the inhabitants of that country call capitan 

 and giiapiicha. The one is an atherine, and the other a new 

 fienus of apodes, that I am about to describe in this memoir. 

 The form of its tail and its anal fin distinguish it sufficiently 

 from the genus trichmrus, which is also found in the fresh 

 waters of South America. I have designed this non-descript 

 fish at the place ; and Messrs. Lacepede and Cuvier, who 

 have willingly examined my descriptions, like me, consider 

 it a new genus well characterized. 1 have named it cremo- 

 philiis on accout of the solitude in which it lives at so great 



• From Reaicil d'Oh.ervalioiis cle Zoologic el d'Anatomie compare, Ue\irTWoa. 

 ComiTiuiiicated by a corrcspoiident.J 



f The Freuch toi»e is about sil feet four inches ninp-tpnth? English. 



an 



