HISTORY OF THE 7VMERICAN MENHADEN. 27 



length of the body, aiul the greatest width of the head (.13) slightly 

 exceeds the half of this. The width of the iuterorbital is about equal to 

 the diameter of the orbit and slightly more than one-fourth the length 

 of the head. The maxillary reaches to the vertical from the i^osterior 

 margin of the j)upil ; the mandible nearly to the vertical from the pos- 

 terior margin of the orbit. The length of the maxillary is about equal 

 to that of the longest ray of the dorsal fin (.15 to .10) ; that of the mandi- 

 ble (.19), to half the distance from the origin of the anal to the origin 

 of the dorsal (.38), or to the length of the base of the anal (.18). The 

 distance from the tip of the snout to the center of the orbit (.13 to .13g) 

 equal the greatest width of the head. The length of the operculum is 

 equal to that of the eye ; the opercular striations are fine, but distinct 

 and numerous. The dorsal fin is inserted posteriorly to a point equidis- 

 tant from the snout and the base of the caudal, and in advance of the 

 vertical from the insertion of the ventrals. Its length of base (.20 to .21.^) 

 is double that of the operculum. Its greatest height is nearly half the 

 length of the head. It is composed of 19 rays, of which the third is the 

 largest. Its upper edge is slightly emarginated. The height of the last 

 ray (.10) is equal to half the length of the base. The distance of the 

 anal from the snout is slightly less than three-fourths of the length of 

 the body (.70-.72); its length of base (.18-.18^) one-fourth of this dis- 

 tance. The distance from the origin of the pectoral to the origin of the 

 dorsal (.37-.37^) is about equal to that from the origin of the anal to 

 that of the dorsal (.38). Its height (.9-.9J) is about half its length of 

 base ; its least height (at last ray), one-third of the same (.G-.5J). The 

 fin is composed of 22 rays, its edge slightly emarginated. The caudal 

 fin is much forked and elongate ; the middle caudal rays (.08) half the 

 length of the maxillary ; the exterior rays above (.31-.32) twice that 

 length ; the lower exterior rays (.35-.34) nearly equal to twice the 

 length of the mandible. 



The pectoral fin is strong, falcate, inserted under the angle of the 

 suboperculum at a distance from the snout (.35-.34) about midway to 

 the insertion of the anal. Its tip extends beyond the insertion of the 

 ventrals, its length (.22) being nearly two-thirds that of the head. The 

 axillary appendages are half as long as the fin, or more. 



The distance of the ventral from the snout (.54-.55) is about the same 

 as that of the dorsal, though by the contour of the body it is thrown 

 slightly behind the point of dorsal origin. Its length (.10) is equal to 

 that of the last ray of the dorsal. The scales are quite regularly arranged 

 in about 24 to 25 horizontal and 50 vertical rows. Their free portion is 

 narrow and high. They are entire at the edges and fluted or crenulated. 

 There are two rows of differentiated scales upon each side of the dorsal 

 line, but they are scarcely pectinated. The scales forming the sheath 

 at the base of the pectoral are large and round. Color : silvery, with a 

 brassy sheen upon the sides and greenish-gray upon the back. 



