XVill INTRODUCTION. 
The Cyprinodontine are the oviparous Cyprinodonts, and are found at the present 
day in America from the Northern United States to Argentina, in Africa, and in 
Southern and Eastern Eurasia. Of nearly 120 species of this group, about 60 are 
North American, 20 South American, and 30 African. 
Prolebias, with several species from fresh-water deposits of the Oligocene and 
Miocene of France, Germany, and Sicily, is probably not distinct from Fundulus, 
which is in some respects the most generalized of living genera. Fundulus includes a 
large 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. | 
Lhe North-American Cyprinodon is represented in the Mediterranean district by 
the living genus or sub-genus Lebias and the extinct Rachylebias 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 Fundulus but little. 
Some of the African species may be placed in Fundulus or in the allied Indian genus 
Haplochilus; the rest do not depart widely from this type. The South-American 
Cyprinodontine are the genera Rivulus, Cynolebias, and Orestias, which differ from 
Fundulus in having the margins of the eyes not free and in other characters of 
specialization. Four species of Rivulus are known from Southern Mexico and Central 
America. A consideration of the distribution of the Cyprinodontine leads us to 
suppose that they were originally a holarctic fresh-water group and that they have 
spread 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 Cyprinodontide are exclusively American and may be arranged in 
three groups—Characodontine, Peeciliine, and Anablepine.. The Characodontine are 
characteristic of and almost peculiar to the system of the Rio Lerma (including the 
Valley of Mexico). oogoneticus comprises four species from the Lerma System, which 
may be defined as Lunduli of the type of F. punctatus, but viviparous and with the 
anal fin of the male modified, the anterior 5 or 6 rays being short and stiff and 
separated by a notch from the rest of the fin. Fundulus punctatus is found in all the 
Pacific coast streams from Oaxaca to Ecuador, and probably enters the sea; it may be 
regarded as nearly representing the ancestral form from which Zoogoneticus has evolved. 
Limnurgus (one species), Characodon (five species), and Goodea (seven species) 
differ from Zoogoneticus in their more specialized dentition, A species of Characodon 
