Geographic and Geologic Relations 419 



mately from Asia Minor northward through West Siberia. 

 So Carassius, that evidently migrated through N. China and 

 E. Siberia into Thibet, India, and Ceylon, spread even 

 to Syria and Eastern Europe, where it was met by Leuciscus 

 in its eastward progress. 



But Barbus, Capoeta, Labeo, and Barilius, all eastern 

 types in their primitive derivation, as we would view the 

 matter, ultimately worked south-westward into the great 

 central African lake region, and there became intermingled 

 with Characinidae, Cichlidae and other families, which 

 came in directly from the South American continent. If 

 it be objected that the above four genera may have entered 

 Africa from the S. American continent, and thence spread 

 eastward by way of Syria, Persia, and Afghanistan to 

 India, China, Tibet, and Japan, we would reply that very 

 few of the family live or have lived in S. America : nor do 

 any of the above-named four genera, which have their 

 headquarters in the East, occur even in N. America. Fur- 

 ther, the western and African genera in particular show no 

 species in the extreme west of Africa, that connects with 

 American species. Connection with European species is 

 also unlikely, since a wide Cretaceo-Tertiary sea separated 

 the two continents during a long period. 



The Lobotinae (or Cobitidinae) probably evolved from 

 some genus of the Cyprininae by increase in barbels, and 

 specially by formation of an osseous casement to the swim- 

 bladder. The genus Botia, that is distributed from Japan 

 to India, Siam, and Borneo, indicates the possible existence 

 and derivation of such a type. The entire group extends 

 from China and Japan, westward to Sweden and Holland, 

 as well as southward to Ceylon, Borneo and Syria. The 

 not unfrequent gradual reduction In size of the scales, and 

 restriction of them over the body In some species, up to their 

 ultimate absorption, has already been drawn attention to 

 and is observed also In other families. 



The fourth sub-family oir Homalopterlnae Indicates 

 derivation In S. E. Asia from some genus that combined 

 characters of Culter of the Cyprininae, and those of Cobi- 

 tidinae. The former shows, among other characters, a tri- 

 partite air-bladder with the median posterior lobe minute, 



