146 MEMOIRS OF THE CARNEGIE MUSEUM 



Tachisurus nuchalis Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 1888, 



145 (name only); Occasional Papers Cal. Acad. Sci., I, 1890, 86. — Jordan and 



EvERMANN, Bull. U. S. Nat. Mus. No. 47, I, 1896, 131. 



There is no doubt that the specimens recorded below are identical with the 

 nuchalis of Giinther, the types of which I have examined. Whether or not the}'' 

 are identical with spixi is not quite so certain. 



Several specimens, 128-235 mm. Georgetown market. (C. M. Cat. No. 

 1287a-c; I. U. Cat. No. 11781.) 



Several specimens, 140 mm. Mahaica. (C. M. Cat. No. 1732.) 



Head 3.6-4; depth 5-5.5; D. 1,7; A. 21. Eye 1.5-2 in the snout, 5-6.5 in the 

 head, 2.75-3 in the interocular. 



Body compressed, especially towards the caudal fin, the depth greater than 

 the width. Head narrowed forward, its greatest width 1 .33 in its length, its greatest 

 depth 1.5; width at the mouth 2.2 in the length of the head. Top of the head 

 granular in the young, the granules becoming more or less united in the adult, 

 forming fine reticulating ridges, especially on the occipital process; occipital process 

 longer than broad, with a blunt median ridge, the margins concave. Fontanel 

 narrowing without interruptions, continued as a deep tapering groove to near the 

 base of the occipital process; interorbital area with four ridges; opercles and hu- 

 meral process rough, covered with skin; sides of the head and snout with reticulating 

 mucous canals. 



Maxillary barbels varying in extent, from about the middle of the pectoral 

 to the base of the ventrals; post-mental barbels extending to base of pectoral or 

 to near its tip; mentals to edge of gill-membrane or to beyond base of pectoral. 



Upper jaw projecting; lips more or less papillose; teeth on the premaxillary 

 and the outer ones of the mandible villiform; the inner series of the mandible 

 and the palate granular; the palatine patches of teeth small, subovate, sometimes 

 contiguous in front. 



Gill-membranes united, joined to the isthmus, a very narrow free margin 

 across it. Gill-rakers 6 + 11-13. Pectoral pore moderate. 



Distance of dorsal spine from snout 2.33-2.64 in the length; the spines 1.2-1.5 

 in the head, serrated on its inner margin, granular or almost smooth on its outer 

 margin. Distance of adipose from the dorsal fin 3.2-3.6 in the length, the adipose 

 fin shorter than the dorsal fin, free posteriorly. Caudal forked, the upper lobe 

 slightly the longer, 4-5 in the length. Anal fin scarcely longer than high, its highest 

 ray about 2 in the head. Ventral fin 1.66-2 in the head. Pectoral spine strong, 

 about as long as the dorsal spine, serrate on its inner margin, granular or scarcely 

 roughened on the outer margin. 



