334 Annals of the Carnegie Museum. 



No. 25550-/;, 6.5 and 7.1 cm., Sao Francisco, Bolivia, Paraguay basin, 



June 10, 1905. 



Depth is respectively 1.84 and 2.16 in the length. 

 No. 25560-^, 5.8 and 6.2 cm., Porto Alegre, Rio Grande do Sul, 



Jan. 19, 1909. 



These specimens are identical with the specimens having three anal 

 spines taken in the Rio Sao Francisco, which I identify as Cichlasoma 

 bimacidatum. They were rare and were taken along with the common 

 forms having four anal spines. Cichlasoma himaculatum is the 

 northern form, and as a rule has four anal spines, while y^quidens 

 portalegrensis is the southern form and as a rule has three anal spines. 

 I collected only one specimen with four anal spines in the La Plata 

 basin, and I feel sure that it is an aberrant individual of the three- 

 spined form. The only known specimen of Acara guianensis (Regan) 

 similarly has but three anal spines. It should be associated with 

 C. himaculatitm. Unless I am mistaken in these observations there 

 would seem to be no line of demarcation between the genera Cichla- 

 soma and Mquidens. 

 No. 2557a-/, Sao Luiz de Caceres, Alto Rio Paraguay, May 24, 1909. 



All of these specimens have depths less than 2 in the length. 



One has four anal spines, but inasmuch as they were all of the 

 same size and taken at one haul of the net, I feel sure that the four- 

 spined specimen is simply an aberrant form. 

 No. 2558a-c, 5.5 to 6.5 cm., Salto das Cruzes, Rio Tiete, Sept. 22, 



1908. 



Two of these specimens have no caudal spots. 

 No. 2559, 8 cm., San Joaquin, Bolivia (Marmore basin), Sept. 4, 1909. 

 No. 25600-e, 1.6 to 6 cm., Corumba, Rio Paraguay, April 27, 1909. 

 No. 2561, 2 cm., Urucum Mts., near Corumba, May 2, 1909. 

 No. 2562, 3 cm., Uruguayana, Rio Uruguay. 



This specimen, as well as some others, has the soft dorsal very 

 faintly scaled. This fact, together with some erroneous cases of 

 classification (for instance, the ^quidens tetramerus of Eigenmann 

 [Annals Carnegie Museum, IV, 1907, 144] has scaled vertical fins, 

 and is thus Mquidens portalegrensis), has extended the range of A. 

 viltata and A. tetramerus, neither of which has been taken in the La 

 Plata basin. 

 No. 2563, 2.5 cm., Puerto Suarez, Bolivia, May 7, 1909. 



The basal halves of soft dorsal and anal, and the entire spinous 



