viii rKKFACE 



TIh' Flatfishes aro one of tlie most interesting groups of fishes to the scientific 

 zooloKist on account of their remarkable departure in general symmetn,' from the 

 bilateral shape which is characteristic not only of the vast majority of fishes, but ol 

 the vertebrates in general. The evolutionary steps by which this modification has 

 been brought about in the natural history of the grouj), and the ontogenetic modifi- 

 cations by which it is brought about in the history of the individual, have been 

 extensively discussed and described without the interest of the facts having been 

 exhausted, and possibly without all the facts themselves having been brought to 

 light. When it is added to this that the group includes some of the most important 

 and valuable food-fishes in various parts of the world, it is somewhat surprising to 

 find that there has been no attempt at a comprehensive systematic revision since the 

 publication of Volume IV of I3r- Giinther's Catalogue in 1862. The families dealt 

 with in the present volume were represented in tfiat Catalogue by 22 genera and 

 00 species. These numbers are here increased to 82 genera and 300 species. Of the 

 species no less then 247 are now represented in the Museum collection : 8 have 

 fieen studied by the author in the collections of other museums, 21 were examined 

 by Colonel Tenison in America, and only 2.4 have had to be included solely on the 

 evidence of the published descriptions 



\V. T. CALMAN, 



Bkitism Muskum (N.\TrK.\L HlsTOKV), Kefpcr nf /iioltigy. 



Jannarx iilh, 1034. 



