xvni IXTEODUCTIOX. 



The Cypviuodontinse are the oviparous Cyprinodonts, and are found at the present 

 day in America from the Nortlicrn United (States to Argentina, in xlfrica, and in 

 Southern and Eastern Eurasia. Of nearly lliO species of this group, about GO are 

 North American, 20 South American, and 30 African. 



ProJehias, with several species from fresh-water deposits of the Oligocene and 

 Miocene of France, Germany, and Sicily, is probably not distinct from Finidnlus, 

 which is in some respects the most generalized of living genera. Fwnduhis includes a 

 h\rge number of species from the coasts and rivers of the United States ; a few species 

 occur in Mexico and Central America, Southern Europe, and Africa. 



The North-American Ci/pri)iodon is represented in the Mediterranean district by 

 the living genus or sub-genus Lehias and the extinct Pacliijlehias of the Upper 

 Miocene ; several of the species enter brackish or salt water. 



The Cyprinodonts of India, the Malay Peninsula and Archipelago, China, and 

 Japan are few in number and belong to genera which differ from FunduJns but little. 

 Some of the African species may be placed in Fundulus or in the allied Indian genus 

 IlajjIocJdlus; the rest do not depart widely from this type. The South-American 

 Cyprinodontina; are the genera Ilimdus, Cijnolebias, and Orestias, which differ from 

 Fundulns in having the margins of the eyes not free and in other characters of 

 specialization. Four species of Bivulus a,re known from Southern Mexico and Central 

 America. A consideration of the distribution of the Cypvinodontinae leads us to 

 sup])ose that they were originally a holarctic fresh-water group and that they have 

 sjiread southwards; the African forms are probably derived from immigrants from 

 Europe and India ; the South-American genera have evolved from a North-American 

 stock, which probably reached the southern continent by migration along the coast. 



The viviparous CyprinodontidiT? are exclusively American and may be arranged in 

 three groups — Characodontiuic, ra'ciliinie, and Anablepinae. The Cliaracodontimc are 

 characteristic of and almost peculiar to the system of the Rio Lerma (including the 

 Valley of ^Mexico). Zoor/uiuficiiti comprises four species from the Leraia System, which 

 ina\ be defined as Fundnli of the tyi)e of F. 'panctatan, but viviparous and with the 

 anal tin of the male modified, the anterior 5 or G rays being short and stift' and 

 separated by a notch from the rest of the tin. Fiuiduliis paiictatus is fuund in all the 

 i'acitic coast streams from Oaxaca to Ecuador, and probably enters the sea; it may bo 

 regarded as nearly representing the ancestral form from which Zoogo)ietkns has evolved. 



Limnurgns (one species), Characodon (tive species), and Goodea (seven species) 

 difler from Zoo<jonetkus in their more specialized dentition. A species of Cliarucodoib 



