434 Transactions. — Miscellaneous. 



St. Catharina Fritz Mueller found a second species of it. The 

 distribution of Parastacus is very peculiar. As well as in Chile 

 species of this genus are found in Entrerios in Argentina 

 (Burmeister), Uruguay (E. Berg), Eio Gi'ande do Sul (Hensel, 

 von Jhering), and St. Catharina (Fritz Mueller). The species 

 of Chilina show exactly the same distribution. A short time 

 ago I received a new species, standing between fiiiminea and 

 gihhosa [Chilina muellerl, mini), which was collected by Mr. 

 Fritz Mueller in the Itajahy, in St. Catharina, where it is 

 common on stones with Lithoglijijhus lapidum. This district 

 will probably extend to Parana, but it is not very likely that it 

 will go as far as Rio de Janeiro, where many naturalists have 

 been collecting. The rivers near Eio de Janeiro flowing to 

 the Atlantic Ocean show a special fresh-water fauna, chiefly 

 Naiadae, whilst those from St. Catharina are more like the 

 forms from Chile. I know about one dozen species of Unio 

 from Chile, and six of them are also found in Rio Grande do 

 Sul or in La Plata. These are the following : Unio diplo- 

 (lon, U. leindior, U. montanus, U. beskeanus, U. hoseritzi, U. 

 auratus, U. rhuacoiciis, U. casahlanccB, U. cethiops, U. viodes- 

 tus, (J. charmanus, U. colcliaguensis, U. faba. 



Evidently we have to deal here with a coherent fresh- 

 water area, which no doubt in ancient times formed also a 

 geographically uniform and united territory, for which I pro- 

 pose the name of Archijjlata. This land, low-lying and 

 abounding with rivers and swamps, must have been in ex- 

 istence before the upheaval of the Andes, because this is the 

 only way by which we can explain the distribution of forms 

 bound and limited to fresh water. The chain of the Andes would 

 have proved an insurmountable obstacle to them, as it really 

 did later on for all the immigrants from north to south, such 

 as Anodonta, Ilycetopus, &c., or Ampullaria, and to the alli- 

 gators and tortoises, the CharacinidcB, Chromidcs, &c., and to 

 the representatives of a new tropical fresh-water flora, such as 

 the species of Victoria and Pontederia. All these are missing 

 in Chile, for the only reason that the upheaval of the Andes 

 had commenced when they began to spread into Archiplata. 

 The Andes may not have been very high then, but they formed 

 a sufficient barrier to prevent migration to the west. 



This Tertiary influx has changed the flora and fauna east of 

 the Andes to an enormous extent. The fresh-water fishes, 

 two only of which are known to me as common to Chile and 

 Rio Grande do Sul — Gobius and Trichomycterus — wei-e retreat- 

 ing southwards, or perished in the struggle with the new 

 immigrants. It is the task of future investigation and re- 

 search to discover the complete flora and fauna of this Archi- 

 plata area. Many things will be understood through it : thus 

 the distribution of the penguins {Spheniscus viagellanicus) found 



