4O4 CALIFORNIA ACADEMY OF SCIENCES. 32 



of gill -rakers flexible. Scales firm, enamelled at base, 

 with strongly marked longitudinal striae, becoming bony 

 when dry; used by the Indians for ornamental work. 

 Lateral line well developed. Dorsal somewhat nearer 

 snout than base of caudal, before ventrals, its first ray fal- 

 cate, its last produced in a short filament, longer than pupil. 

 Base of fin with a large scaly sheath; pectoral and ventral 

 with scaly axillary appendage. Anal similar to dorsal, 

 but much smaller. Pectorals and ventrals rather small; 

 caudal very long, forked to the base, its lobes subequal, 

 straight; base of fin with small scales. Ventrals some- 

 what falcate. 



Brilliant silvery in color, greenish above; fins more or 

 less darker; inside of pectoral and ventral blackish. 



Stomach forming a muscular crop. Pyloric caeca many. 

 Intestinal canal long, filled only with remains of plants. 



The skeletal peculiarities of Chanos are numerous and 

 remarkable, many archaic characters persisting. The 

 following account of the skeleton has been prepared by 

 Mr. Starks: 



SKELETON OF CHANOS CHANOS. 



a. Cranium. 



The frontals are very large, covering nearly the whole 

 top of the head, and extending over the dorso- anterior 

 part of the parietals, supra-occipital and the parotic pro- 

 cess. 



On the side of the skull there is an area bounded by 

 the supra-occipital, the opisthotic and the sphenotic, which 

 is not ossified but is composed of cartilage. 



Between the frontals, at about their middle, there is a 

 place in which the bone is fibrous and largely cartilagi- 

 nous; it is easily broken through. 



The basal cavity under the brain cavity is large. 



