140 Annals of the Carnegie Museum. 



slightly ; sometimes there are but four or three teeth, in which case 

 the first and last are directed forward and the other one or ones are 

 withdrawn from the line connecting them. Dentary with four large, 

 many-pointed teeth and several small, mostly conical ones on the side. 

 Dorsal considerably behind the ventrals ; adipose well developed ; 

 anal margin oblique, but little concave ; ventrals small, not reaching 

 anal ; pectorals not ventrals. A small humeral spot ; a well-defined 

 silvery lateral band from in front of dorsal to caudal ; middle caudal 

 rays, margin and tips of caudal lobes black. 



Deuterodon 13 Eigenmann gen. nov. 



A genus of Tetragonopterin?e distinguished as most of the genera 

 of Caracidse by its dentition. 



Teeth in the premaxillary in two series, those of the outer series 

 few (2 on each side), and separated from each other, expanded at the 

 tip, each with a large median and two small lateral cusps ; teeth of the 

 second row very broadly expanded at the tip, each with a long, pointed 

 median cusp and three graduated cusps on the sides ; the teeth becom- 

 ing smaller, but not notably so toward the sides, 5 on each side ; 

 maxillary with a few (2 on one side, 3 on the other), similar teeth; 

 mandible with a single series of teeth, 10 on each side, regularly 

 graduated from in front back ; the teeth little expanded at the tip, 

 each with a large and strong median cusp and two or three much 

 smaller lateral cusps ; the teeth and jaws so arranged that their action 

 is shear-like, in contrast to Astyanax and related genera where the 

 lower jaw is apparently thrown forward when opened and its anterior 

 teeth point up and back when it is closed, the arrangement being 

 similar to that in the Mylinae, the second series of teeth in Astyanax 

 being further back than in the present genus. Gill-rakers setiform 

 as in Astyanax ; no precumbent dorsal spine ; nares close together ; 

 gill-membranes free from the isthmus and from each other ; lateral 

 line complete. Eats plants. Its teeth enable it to cut out pieces of 

 aquatic plants with great neatness. 

 71. Deuterodon iguape Eigenmann sp. nov. (Plate XLI, Fig. 3). 



Type No. 9265, a specimen no mm. long from Iguape collected 

 by Dr. H. von Ihering. 



Tetragonopterus fasciatus Eigenmann & Norris (not Cuvier). Re- 

 vista Museu Paulista, IV, 357. 



13 Sebrepog repeated, bihvc tooth ; in allusion to the simi rritv of the mandibular 

 eeth. 



