52 



FISHES FROM BRAZIL 



173. Plagioscion auratus (Castelnau). 



Several specimens from 4 to 15 inches in length were collected at Para 

 in the market. These are all very much darker than the other two species at 

 hand, with the exception of one 6 inches long, and, to a less degree, one 

 twice as long. The darkest ones are almost black on the back, the head, and 

 all of the fins, and dark dusky on the lower parts. The lightest one is 

 slightly dusky on the back, the dorsals and caudal ; the balance is without 

 color, the color being as in the other two species. 



This species may be known from Plagioscion surinamensis by the smaller 

 elliptical eye, not so near the anterior profile; the wider, more convex, inter- 

 orbital space, which is from half again as wide as the vertical diameter of 

 the eye to twice as wide. The snout is a little more produced, and the lower 

 I'aw is always included. The length of the pectoral is equal to the distance 

 from the tip of the snout to the preopercle. The first ray of the ventral, in 

 all sizes, is filamentous and projects beyond the other rays about one diameter 

 of the eye. The gill-rakers number 10 or 11. Other differences are in- 

 dicated under the description of Plagioscion surinamensis and in the tables 

 of measurements. 



TABLE OF MEASUREMENTS EXPRESSED IN HUNDREDTHS OF LENGTH. 



Length in mm. to caudal base 



Head in lOOths of length 



Length of maxillary , 



Long diameter of eye 



Width of interorbital , 



Length of snout 



Length of pectoral 



Length of ventral without filament 



Length of second anal spine 



Width of second anal spine 



Length of fourth dorsal spine 



Length of caudal , 



Number of dorsal rays 



Number of anal rays 



174, Plagioscion surinamensis (Bleaker). 



A few small specimens and one large one, a little over a foot in length, 

 were collected at Para. They are all very light in color ; only slightly dusky 

 above and on the edges of the dorsal fins. This species appears from litera- 

 ture to be much more rare than the other two here reported upon, and it was 

 not found nearly so abundantly in the market during our stay at Para. 



