282 



MEMOIRS OF THE CARNEGIE MUSEUM. 



gill-membrane free or very narrowly joined to the isthmus; first pectoral ray not 

 continued as a filament; opercles and interopercles with numerous spines; dorsal 



AC D 



Fig. 2. A-C. Halcheria patagoniensis Eigenmanii. A. Skull from above. B. Opercular appar- 

 atus, etc., as seen from above when attached to the skull. C. The same spread out flat. D-E. Sclero- 

 nema operculatum Eigenmann. D. Skull from above. E. Opercular apparatus spread out flat. 1, 

 Premaxillary; 2, ethmoid; 3, lateral ethmoid; 4, nasal; .5, frontal; 6, sphenotic; 7, pterotic; 8, supra-occipi- 

 tal; 9, epiotic; 10, supraclavicle; 11, parapophysis of coalesced vertebrae; 12, maxillary; 13, palatine; 14, 

 metapterygoid; 15, quadrate; 16, pre-opercle; 17, interopercle; 18, opercle; 19, hyomandibular; 20, man- 

 dible. 



long, emarginate; caudal peduncle slender, the fin wider than the peduncle, with 

 few accessory rays; origin and end of anal under the long dorsal, except in H. 

 areolata. 



Habitat. — In the mountain-streams of northern Argentina, central Chile, and 

 southward. Replacing the species of the genus Pygidium east of the Andes in the 

 south, and largely also west of the Andes. Its definite boundaries not known. 



Key to the Species of Hatcheria. 

 a. Dorsal with fourteen to seventeen rays. 



b. Origin of dorsal equidistant from tip of caudal and some part of the snout; D. 15; last ray of anal 

 under the last ray of the dorsal or very little farther forward, 

 c. Distance between anal and caudal 4.5 in the length; origin of ventrals nearer the caudal than 

 the snout; origin of anal nearer tip of caudal than head; origin of dorsal equidistant from 



tip of caudal and posterior nares 1. patagoniensis Eigenmann. 



cc. Distance between anal and caudal 3.75 in the length; origin of ventrals nearer snout than to 

 caudal; origin of anal nearer the head than tip of caudal; origin of dorsal equidistant from 

 tips of snout and caudal 2. maculata (Cuvier & Valenciennes). 



