NO. 2027. FISHES OF THE OENUS 0SMERU8—FISK. 295 



the mouth. The dentition is stronger than in either Osmerus thdl- 

 eichthys or Osmerus starksi, and on the tip of the tongue there is a 

 single curved tooth not found in the other species. 



The head is contained 4 times in the total length without caudal. 

 The snout is more pointed than that of Osmerus thdleichihys or 

 Osmerus starTcsi, and lacks the shallow indentation at its end which 

 characterizes the other two. It is contained in the head 3^ times. 

 The maxillary is contained 2 to 2^^ times in the head, and reaches 

 three-fourths of the diameter of the eye to a point opposite its pos- 

 terior margin. The lower jaw is sharper and more slender than in 

 the other two species, and projects rather strongly. The eye is con- 

 tained 4^ times in the head, and its diameter is slightly less than the 

 interorbital width. The interorbital space is contained 4 times in 

 the head. The opercle is somewhat translucent and bears striae 

 similar to those in Osmerus starTcsi. The gill rakers number 11 or 

 12 + 22 to 25, and the longest one is contained twice in the eye. 



The depth, in the length without caudal, is 6^ to 7|. The depth 

 of the caudal peduncle is contained 4 times in the length of the head. 

 The number of scales along median line of back from occipital 

 region to caudal is 70 to 74. 



The fin rays number: Pectoral, 12; ventral, 8; dorsal, U to 12; 

 anal, 15 to 16. The pectoral is contained 1§ to 1| times in the head; 

 the ventrals, 1§ times; the dorsal, 1|; the anal, 3; and the caudal, 

 1|. The distance of the dorsal from the tip of the snout is If to 1| of 

 the total length without caudal — greater than in either Osmerus 

 thaleichthys or Osmerus starTcsi. The distance of the ventral from 

 the chin is slightly less than the distance from the dorsal to the 

 tip of the snout. The distance between the origin of the pectoral 

 and the origin of the ventrals is contained 3 J times in the length. 

 The pectoral extends to a distance equal to twice the interorbital 

 space from the origin of the ventrals. The ventrals reach to within 

 1 \ the diameter of the eye from the vent. The distance between the 

 posterior insertion of the dorsal and the anterior insertion of the 

 adipose dorsal is contained 1 ^ times in the head — less than in Osmerus 

 tJialeicTitTiys or Osmerus starTcsi. The distance between the origin of 

 the pectoral and the origin of the ventrals is greater than in the 

 other two species, as it equals 1| times the length of the head. The 

 anterior origin of the ventrals is one-half the diameter of the eye in 

 front of the anterior origin of the dorsal. The tip of the dorsal ex- 

 tends to a point one-half of the diameter of the eye in front of the 

 origin of the anal. The adipose dorsal is placed slightly anterior to 

 the posterior insertion of the anal. 



Here described from 10 specimens taken from San Francisco Bay, 

 collected by N. B. Scofield. 



