OCT., 1907. FRESH-WATER FISHES MEEK. 157 



of 150 mm. it is difficult to say which is the oldest because they grow 

 so irregularly. The incisor-like teeth have the appearance, however, 

 of becoming more developed in this species with age, though perhaps 

 very irregularly so. I do not believe that we can retain the genus 

 Herichthys on the character of dentition alone. The genus Neetroplus 

 is based on the incisor-like teeth of N. nematopus, but these flat 

 truncate teeth are quite different from the more or less compressed 

 truncate or rounded anterior teeth which we usually find in many of 

 the larger individuals of the species in question. So far as I have 

 studied them, by far the larger number of the Cichlasoma appear to 

 have a quite uniform and regular dentition. The teeth in the young 

 are conical and pointed, while usually in the larger and apparently 

 older individuals some or all of them are more or less blunt at the 

 tips. To give this character specific or generic value one must distin- 

 guish between teeth which are worn or changed by age, and those 

 whose structure is constant, but to do this is very difficult. 

 Roderiguez (5), 30 to 55 mm. 



