CichUd Genera Ciclila, (ylisctobiaiicliu-», (C--. '1?>\> 



The 23 genera eomprisc 1 19 species, of which 85 arc 

 Soiitli Anierieaii. The exclnsively South-American irencra 

 are Cir/i/a (3s])eeies), Cha'tohrnnrhiis {'I), Clifefobranckopsis 

 (1), Crenacara (2), Jiuirac/ioj/s (5), Crenic'ichla (10), Nuiina- 

 cnra (1), Acarojisis (1), Aslronntus (1), Retrocalus (1), 

 Ilclcrofiramnia (5), Biotoecux (I), Uaru (1), Si/inpfn/sodofi (I), 

 and Ptero/j/iy/lum (2). Acara has 18 species in South 

 America and 1 in Panama, Geophngns 11 iu South America 

 and 1 in Panama, and CAclilosoina 13 species in South America, 

 53 in ^Mexico and Central America, 1 in Cuba and 1 iu 

 Parbafloes. The remaining? genera all p'-rtain to Mexico aiul 

 r'entral America, one species of Ht^-iclitlu/s reaching Texas. 

 They are Pet-nia i\ species), Ht'richtlnjs (3), Paraneeiroplus 

 (1). Neetroplua (1), and Herotilapia (1). 



It is interesting to note that not <me of tl:e genera with 3 

 anal spines is found north ot the Isthuius of Pauauui aiul 

 that all the South-American forms have simple conical teeth. 

 Tlic South- American species Avith more than 3 anal spines 

 are either those species of Cichlosoma which come nearest to 

 Acara or else may usually be regarded as directly modified 

 from them, whilst the jjenera peculiar to Mexico and Central 

 America are exaggerations of the types of Cichlosoma found 

 there. 



Witli the exception of Cic/i/n, and possibly of CIkeIo- 

 branc/n/s, Acara is the starting-point for the evolution of tlie 

 genera inhabiting South America; of these Cichlosoma only 

 has reached Central America and Mexico, and has there 

 given rise to a variety of still more specialized forms, very 

 few of which have again s|)read southwards^, 



^Vllen we eon-ider that the Ciehlid fauna of ^Mexico and 

 Central America has undoubtedly been derived from South 

 America, that the most primitive South-American genus, 

 Acara, is scarcely generically distinct from the African 

 Parafilapia and that there is no reason to believe that the 

 Cichlids have ever been other than a freshwater group, we 

 may find in them considerable support for the view that there 

 was a land-connexioLi between South America and Africa in 

 Eocene times. 



Priscacara, from the Eocene of Wyoming and Utah, has 

 been regarded as a Ciehlid, but it has not the reduced 

 number of branehiostegals nor the toothless palate which 

 characterize all liviug Cichlidic, and appears to me to have 

 no bearing on their geograjdiieal distrd)utio:i. 



* Cichlosoma ornntum and C. Fesfte from W. Ecuador, C. Kraussi 

 from Ct'lorafjift and Venezuela, and C. spectabtle from the .\mazou bclonij 

 to Central-American tvpea. 



17* 



