EIGENMANN: CATALOGUE OF FRESH WATER FISHES. 



Ai. fiLquidens tetramerus (Heckel), 



Pellegrin, 135. 



? Scicena punctata Linnaeus; Acara vi- 

 ridis, diadema, pallidus and dimerus 



Acara viridis 

 Acara diadema 

 Acara ^'ittatus 



Acara pallidus 

 Acara dorsigcrus 

 Acara marginatus 

 Acara dimerus 



Acara nassa 

 Acara cognalus 

 Acara unicolor 



Acara crassispinis 



Heckel enumerates 

 genus : 



Acara nilolicus 

 Acara punctatus 

 Acara gronovii 

 Acara brasiliensis 

 Acara ttznia 

 Acara surinamensis 

 Acara desfontainii 

 Acara ocellatus 



B. 



= jEquidens tetramerus. 

 = /Equidens tetramerus. 

 = /Equidens vittatus. 



C. 



= sEquidens tetramerus. 



= sEquidens dorsigerus. 



= Cichlasoma bimaculatum. 



= sEquidens tetramerus. 



D. 



= Acaropsis nassa. 

 = Acaropsis nassa. 

 = Acaropsis nassa. 



E. 



= Astronotus ocellatus. 

 as other species belonging to this 



= Tilapia nilotica. 



= Cichlasoma punctatum. 



= Cichlasoma bimaculatum. 



= Ceophagus brasiliensis. 



= Cichlasoma bimaculatum. 



= Geophagus surinamensis. 



= Astatotilapia desfontainii. 



= Astronotus ocellatus. 



Inasmuch as the species described by Heckel in- 

 cluded members of four distinct genera and since he 

 added members of three other genera from species 

 known to him from descriptions, we cannot say that he 

 had any very definite thing in mind when he framed 

 the genus. 



In the generic description he refers to figures of the 

 lower pharyngeals and gill-arches of Acara tetramerus 

 and crassispinis. 



As far as Heckel's work is concerned, his Acara, 

 containing the type of Swainson's Astronotus (to the 

 figure of which Heckel definitely refers in his generic 

 description) might be a synonym of Astronotus or 

 separate from it, depending altogether on which of his 

 species, if any, he considered his type. If any presump- 

 tion is permitted, it must be in favor of his first species 

 or the last, or one of the species whose figures are 

 referred to in his generic description. The first species 

 is a synonym of Sci&na bimaculata Linnaeus and be- 

 longs to the genus Cichlasoma of Swainson. If the 

 first species is selected, the name Acara becomes a syn- 

 onym of Cichlasoma. If the last species, crassispinis, 

 is selected, Acara becomes a synonym of Astronotus, 



Heckel; Chromys punctata and uni- 

 ocellata Castelnau. 



Habitat : Essequibo ; Amazons south to 

 Rio Janeiro and Paraguay. 



since crassispinis is a synonym of ocellatus, the type of 

 the latter genus. If one of the two species figured is 

 selected we may have tetramerus or again crassispinis 

 as the type for Acara. If the former is selected the 

 name Acara will stand. 



Inasmuch as Heckel does not select a type, it is 

 incumbent on a later naturalist to select a type from 

 among the four species discussed, or from among any 

 of Heckel's species. 



In the earliest paper by Gill (Synopsis of the Fresh- 

 Water Fishes of Trinidad) he says, p. 19: "As it 

 [Labrus punctatus, the type of Cichlasoma'] is a true 

 Acara, the latter genus is consequently synonymous with 

 Cychlasoma, and in accordance with the law of priority, 

 the Swainsonian name must be adopted as that of the 

 present genus." Gill re-defines the genus Cichlasoma, 

 excluding several of Heckel's species, and continues: 

 " With these characters, that species which Mr. Heckel 

 . . . has described as the Acara crassispinis, will also 

 be excluded [from the genus Cichlasoma'] ; this species 

 appears to be generically distinct from both Cychlasoma 

 and from Astronotus of Swainson. ... If it should be 

 found, on a more critical examination, to be really 

 distinct from Astronotus, to which it is most nearly 

 allied, Heckel's name of Acara might appropriately be 

 retained as its generic name. ... It belongs to the 

 section E of the genus Acara, in the arrangement of 

 Heckel . . . ; the other sections ... all belong to 

 Cychlasoma as now restricted." 



Gill thus removed from Acara all of Heckel's species 

 but crassispinis. 



There can be no question that it was entirely within 

 the province of Gill to restrict the genus to this species. 

 But it was found later that crassispinis is a synonym of 

 ocellatus, the type of Astronotus. Acara is therefore 

 the exact synonym of Astronotus and cannot be used for 

 anything else. Inasmuch as tetramerus and other spe- 

 cies are distinct from Astronotus, I coined the name 

 /Equidens for them in 1894. (Ann. N. Y. Acad. Sci., 

 VII, 616, using the Acara tetramerus Heckel as type.) 



The name Acara has been resurrected by Regan (Ann. 

 and Mag. Nat. Hist. (7), XV, 1905, p. 330), who says: 

 " After removing from Heckel's genus the species 

 which belong to Astronotus, Cichlasoma and Acaropsis, 

 I use Acara for the remainder, regarding Gill's restric- 

 tion of the name Acara to a species which was already 

 the type of another genus as invalid." 



I know of no rule, ancient or modern, of scientific 

 nomenclature which authorizes anyone to regard as 

 invalid the work done by someone else, unless that work 

 was done contrary to the accepted canons. In fact, the 

 rules (if I am not mistaken) have been made especially 

 to prevent this sort of procedure. 



