374 NEW SPECIES OF MEXICAN FISHES. 



the lower jaw projects slightly. The jaws are short and moderately 

 stout, the upper jaw being freely protractile. The length of the upper 

 jaw is slightly more than one-third the length of the head, and equal to 

 the length of the mandible. The teeth are slender, conical, in a double 

 series, of which the outer is enlarged. The mandible reaches to the 

 vertical through the front of the eye ; its position is oblique when the 

 mouth is closed ; its length is slightly more than one-third the length 

 of the head and less than the width of the interorbital space. The eye 

 is one-fourth as long as the head and only two-thirds- of the width of 

 the interorbital space. 



The opercle is connected by membrane to the shoulder girdle, begin- 

 ning at a point about in the line of the lower margin of the eye. The 

 insertion of the dorsal is very slightly in advance of the insertion of the 

 anal and at a distance from the front of the eye equaling about twice 

 the length of the head. Its rays are slender and not very long, the 

 longest being somewhat shorter than the base of the fin and less than 

 onelialf tlie length of the head. The base of the dorsal equals one-half 

 the length of the head. The anal is inserted about under the third ray 

 of the <lorsal: its longest ray is oue- third to two-fifths as long as the 

 head. The anal base is very short, oue-half as long as the dorsal base 

 and very little longer than the eye. 



The pectoral is inserted considerably below the middle of the body, 

 about at the beginning of its lower third, its upper edge being below 

 the level of the lower edge of the orbit ; its length is one-half that of 

 the head. 



The caudal is slightly rounded, its middle rays being one-fifth as long 

 as the total without the caudal. The least height of the caudal peduncle 

 is oue-half the greatest height of the body. The distance from the end 

 of the dorsal to the origin of the middle caudal rays is slightly more 

 than the least height of the caudal peduncle. 



The ventral is situated nearly in the middle of the total length, ex- 

 cluding the caudal ; it does not reach the vent ; its length is about one- 

 third of the head's length. 



D. 15; A. 11; Scales 11-30. 



Coloration in sjnrits. — General color light brown ; the sides with five 

 or six dusky bands, the widest somewhat greater than the length of 

 the eye ; one of these bands is placed under the anterior half of the 

 dorsal. On the sides and head the green color is intermingled with 

 silver. Anterior half of abdomen with a j-ellowish tinge. Cheeks 

 bronze in the upper portion, silvery below. Operculum silvery. 



Lampetra spadicea, ii.sp. (PI. XX, f, fi). 



The U. S. Ntitional IVluseum has had in its i)ossession for several years 

 a larval lamprey received from Guanajuato, Mexico, aud recently Prof. 

 A. Duges, froui whom the earlier specimens came, has sent an adult 

 example. The si)ecimen which forms the type of this description is 7f 

 inches long. Its catalogue number is 38005. 



