1902.] AND ANCIENT GEOGRAPHY. 293 



2. brasiliensis (Mrts.). Southern Brazil : Rio Grande do Sul. 



3. hassleri Fax. Chili : Talcahuano, Tumbez. 



4. defossas Fax. Uruguay. Brazil : Rio Grande do Sul. 1 



5. sajfordi Fax. Uruguay. Brazil: Rio Grande do Sul. 1 



6. varicosus Fax. Reported from Colima, Mexico. 2 



7. nicoleti (Phil.). Chili: Tumbez. 



8. agassizi Fax. Chili: Talcahuano, Llanquihue (Puerto Montt), 



Tumbez. Argentina: Lake Nahuel Huapi. 3 



Doubtful species : chilensis (M.-E.), spinifrons (Phil.), bimacu- 

 latus (Phil.), all three from Chili. 



This genus is also found in Sta. Catharina, Southern Brazil, 

 according to Fr. Mueller. 



6. Genus Astacoides Guér. 

 Species : 



1. madagascariensis (M.-E.). Madagascar. 



As regards the detailed limits of the range of the single species 

 and genera we are very poorly informed, and, further, it is quite 

 possible that our knowledge of the Australian and South American 

 crayfishes is very incomplete also on the systematic side, and it is 

 very likely that there are many unknown species. 



It is evident at the first glance, however, that the distribution of 

 the Parastacidcz is divided into four absolutely isolated areas : 

 Australia (including Tasmania and possibly New Guinea) ; New 

 Zealand ; part of South America ; Madagascar. Within each of 

 these areas are peculiar genera: in Australia, Cheraps, Astacopsis, 



1 1 have received these two species, defossus and saffordi, from Rio Grande do 

 Sul through Dr. H. von Ihering. N 



2 This locality most emphatically needs confirmation. It is very surprising that 

 this species has never been rediscovered anywhere in Mexico, although large col- 

 lections of freshwater Crustaceans from these parts have lately reached the 

 United States Museum. 



3 Through Prof. W. B. Scott, of Princeton, I have received from the La Plata 

 Museum two males and one female of this species from this locality which agree 

 well with the description, with the exception that in the larger (adult) male the 

 right (largei) chela is more elongate, with almost parallel margins, and that the 

 squamiform granules of it are more strongly marked. The smaller male and the 

 female agree perfectly with P. agassizi. 



The lake Nahuel Huapi is situated in the Cordilleras, at the southern extremity 

 of the Argentinian province Neuquen. It drains into the Atlantic through the 

 river Limay Leofu, which finally forms the Rio Negro. This locality is 

 directly east of Llanquihué, in Chili, but on the opposite slope of the Cordilleras. 



