Teeth on the vomer in two slightly separated, oval patches, 

 contiguous with the palatine patches, which are rather more 

 than twice as broad as antero-posteriorly long. 16 stiff, trian- 

 gular gillrakers, ventrally decreasing much in length, the longest 

 about equal to branchial filaments. Brown-grey above, silvery 

 below and on the sides. Fins yellowish, margin of caudal 

 dark. Length over 260 mm. 



Habitat: South New Guinea (Fly river!; Lorentz river 1). 



In tidal part of rivers. 



19. Arius acrocephalus M. Web. 



Arius acrocephalus Max Weber, Nova Guinea IX. livr. 4. 1913, p. 543. 



B. 6; D. I. 7; A. 17; P. I. 10; V. 6. 

 Elongate. Height below dorsal spine 4 J / 2 , head about 3 ! / 3 , 

 its width about i'/ 2 times in its length. Dorsal profile sloping 

 steeply to the snout in a straight line, with exception of a 

 feeble convexity above the opercles. Headshields with feeble, 

 granulated lines. Occipital process with slightly convergent 

 straight sideborders, its truncate hindborder touches the semi- 

 circular basal bone 

 of the dorsal spine, 

 its width at base 

 i ] / 3 in its length. 

 Rhombic median 

 fontanel elongate, 

 reaches to the last 

 V 4 of head. The 

 broad, short hume- 

 ral process with 

 reticulate ridges. 

 Eye 6-6 1 / 2 > almost 

 3 times in the inter- 

 orbital space, more 



Fig. 126. Arius acrocephalus M. Web. /,. than 2 times in the 



prominent snout, 



which is ! / 3 of length of head and which is shorter than the 

 curved gape. Lips thin, only prominent at the corner of the 

 mouth. Maxillary barbels do not reach base of pectorals, 

 mandibulary ones to hindborder of the gillmembrane, mental 

 ones r / 3 shorter. Height of dorsal more than head without 

 snout, its spine scarcely longer than postorbital part of head, 



