eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 143 



Tachisurus grandicassis Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

 1888, 141 (Maranhao; Bahia) ; Occasional Papers Cal. Acad. Sci., I, 1890, 65. 



Netuma grandicassis Jordan and Evermann, Bull. U. S. Nat. Mus. No. 47, I, 

 1896, 126. 

 Several specimens, 335-490 mm. Georgetown market. (C. M. Cat. No. 



1254-1259; I. U. Cat. No. 11777.) 



Fig. 28. Outlines of occipital processes of various individuals of Nolarius grandicassis (Cuvier and 

 Valenciennes). Total length of specimens the processes of which are figured in order from left to right: 

 335 mm.; 435 mm.; 400 mm.; 490 mm. 



Head 3.4-3.75; depth 5.66-6; D. 1,7; A. 18. Eye 3-3.5 in snout, 4-4.5 in 

 interorbital, 8.5-10 in head. 



Body cylindrical in front, tapering to a slender caudal penduncle. Head greatly 

 depressed, profile almost straight, descending, the width of the head 1.33-1.4 in 

 its length, its depth 1.8-2 in its length. Occipital process with a deep constriction 

 where it joins the occiput, shaped like a clover leaflet, much longer than broad, 

 sometimes keeled. Center of the fontanel over the middle of eye, the fontanel 

 not continued backward as a groove. Occipital process, top of head, and humeral 

 process granular; interorbital region with four ridges, the inner ones bounding the 

 fontanel, the outer ones running obliquely backward from near the posterior nares. 



Maxillary barbels reaching to the base of the pectorals, mentals to gill-opening, 

 post-mentals a little longer. 



Upper jaw projecting a diameter of the eye or more, the lip very wide, espe- 

 cially in front, making the nose pointed; teeth of both jaws rather large, those on 

 the palate somewhat smaller; the depth of the premaxillary band 7-9 in its 

 width; the mandibulary band very shallow ; vomerine teeth present in adult; pala- 

 tine patches triangular, produced backward; four patches in adult, the two additional 

 ones placed just back of the two triangular ones in front. 



Gill-membranes meeting in an angle, forming a fold across the isthmus. Gill- 

 rakers 6 + 10. 



Distance of dorsal spine from snout 2.33-2.5 in the length. Distance of 

 adipose fin from the dorsal 3.6-4 in the length; adipose fin at least as long as the 



