A REVIEW OF THE FISHES OF THE GENUS OSMERUS OF 

 THE CALIFORNIA COAST. 



By Mary Fisk, 



OJ Stanford University, California. 



In the following paper, three species of the genus Osmerus are dis- 

 cussed. All three species formerly have been confused with Osmerus 

 thaleichthys. One, Osmerus starTcsi, is a new species, and another, 

 Osmerus attenuatus, has not been recognized since it was described in 

 1880,* by Lockington. 



Grateful acknowledgment is made to Prof. E. C. Starks, of Stanford 

 University, for his able assistance in the preparation of this paper. 



The drawing of the new species is the work of Mr. W. S. Atkmson. 



Key to the species ofOsmems. 



aK Pectorals extending to origin of ventrals; ventrals reaching anus thaleichthys 



a^. Pectorals not extending to origin of ventrals; ventrals not reaching anus. 



¥. Body very slender, the depth 6^ to 7i in length; distance between origin of 

 pectorals and origin of ventrals greater than length of head; pectorals 

 extending one-half the distance to origin of ventrals; commissure of mouth 



nearly straight attenuatus 



¥. Body not very slender, the depth 5 to 5| in length; distance between origin 

 of pectorals and origin of ventrals equal to or less than length of head; 

 pectorals extending more than one-half the distance to origin of ventrals, 

 commissure of mouth curved starksi 



OSMERUS THALEICHTHYS Ayrea 



This species may be known at once by the long pectoral and ventral 

 fins. The former reach to or slightly be3^ond the origin of the ventrals, 

 and the latter extend to the anus. As in Osmerus starJcsi, the com- 

 missure of the mouth is curved, in contrast to the almost straight 

 jaws of Osmerus attenuatus. The gill rakers are longer, and more 

 delicate and slender than in either of the other two species. The 

 dentition is weaker than that of Osmerus attenuatus, and there is no 

 prominent tooth on the tip of the tongue. 



The head is contained in the total length, without caudal, a little 

 more than 4 times. The snout is contained in the head 4 to 4| times. 

 The maxillary is contained twice in the head, and reaches four-fifths 

 the diameter of the eye to its posterior margin. The lower jaw pro- 

 jects slightly. The eye is contained 4 times in the head, and its 

 diameter is slightly less than the interorbital width. The interorbital 



1 Proc. U. S. Nat. Mus., vol. 3, p. 66. 



Proceedings U. S. National Museum, Vol. 46— Nq, 2027. 



291 



