424 On Freshwater Fishes from Madagascar. 
parasphenoid only; articular surface broadly ovate, almost 
heart-shaped. Vertebree 34 (17+17); fourth with a pair of 
very small inferior apophyses ; precaudals with parapophyses 
from the fourth; ribs subsessile. 
Madagascar ; two species. 
This genus is quite distinct from any of the African genera, 
but is closely related to the Indian Etroplus, which differs 
from Paretrop/us in its more generalized dentition, the jaws 
with 2 or 3 series of tricuspid teeth, those of the outermost 
series enlarged, in the adult truncate, often without lateral 
cusps, and the lower pharyngeal with most of the teeth 
slender, uni- or bicuspid, only the two middle rows being 
formed of large blunt teeth. 
The Madagascar Cichlidze belong to three endemic genera, 
two of which appear to be related to West-African genera, 
whilst the third is closely related to, but more specialized 
than, the only Indian genus of the family. Kxcept the 
Cichlids, none of the families of fishes characteristic of the 
fresh waters of Africa occurs in Madagasear, which is popu- 
lated chiefly by freshwater genera or species of marine 
families (Kuhliide, Atheiinide, Hleotride). The Ostario- 
physi, which are dominant in the freshwater fauna of all 
other parts of the world except the Anstralian Region, are 
absent from Madagascar, except for two species of tle endemic 
genus Ancharius, which belongs to the Ariide, one of the 
two families of Siluroids that form an exception to the rule 
that the Ostariophysi are strictly freshwater fishes. 
The presence of Cichlidee in Madagascar is probably due to 
the fact that some fishes of this family are found in waters of 
fairly high salinity. Species of each of the three Madagascar 
genera have been found in brackish lagoons on the coast, 
whilst Htroplus suratensis of India and Ceylon is charac- 
teristically an estuarine fish, and, according to Day, “ extends 
its range into brackish or even saline water.” It is evident 
that Madagascar has not been connected during the Tertiary 
with either Africa or India to an extent that sufficed for the 
passage of true freshwater fishes, but it may have received its 
Cichlid from Africa at a time when it was only narrowly sepa- 
rated from or even temporarily connected with that continent, 
and perhaps from India when the islands of the Indian Ocean 
were more extensive and a brackish-water fish might pass 
from one to another; this time can hardly have been later 
than the beginning of the Miocene. 
