326 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



and membrane of lower jaw blackish anteriorly. Eye with a dusky 

 yellowish streak surrounding tbe iris. Spinous dorsal yellowish below, 

 dusky towards the margin; other vertical fins yellowish, with some 

 scattered black points and with narrow black margins. Pectorals 

 yellowish, the membrane with series of dark points between the rays. 

 Ventrals white, with a dusky yellow blotch on the outer half of outer 

 rays. 



I^umerous specimens, all about ten inches in length, were obtained in 

 the Bay of Panama. 



This species is a member of the typical section of the genus Xenichthys^ 

 which is characterized by the length of the soft dorsal and anal, these 

 being much longer than the spinous part. To this section also belong 

 X. xanti Gill and X. agassizii Steind. The two remaining species, now 

 known {X. calif or niensis Steind. and X.xenurus 3. & G.), have the soft 

 dorsal and anal not longer than the spinous dorsal. 



The species of Xenichthys may be distinguished by the following 

 analysis : 



a. Soft dorsal mucli longer than spinous dorsal, of 14 to 18 rays; anal elongate, with. 

 16 to 1^^ soft rays; form elliptical, the depths about equal to length of 

 head. . Caudal lunate. 

 i. Scales of the lateral line larger than the others; dorsal rays XII, 14; lat. 1. 

 50; eye moderate, 3 iu head, the maxillary not reaching its front; pec- 

 toral short, little longer than ventrals, about half length of head. Pale, 

 with two purplish longitudinal stripes ; an obscure spot at base of cau- 

 dal Xanti.* 



a. Scales of lateral line like the others. 



c. Eye very lai'ge, 2^ in head, the maxillary reaching beyond its front; pec- 

 toral moderate, 1* in head, considerably longer than ventrals ; dorsal 

 rays XI, 18 ; lat. 1. 54. Color silvery, with several faint longitudinal dark 



streaks ; lower fins with dusky points Xenops. 



cc. Eye rather large, 3J in head ; pectoral very long, scarcely shorter than 

 head; dorsal rays XII, 18; lat. 1. 58. Color silvery, bluish above, with- 

 out stripes Agassizii. t 



aa. Soft dorsal shorter than spinous dorsal of 10 or 11 rays ; anal short, of 10 or 11 

 soft rays. 

 d. Caudal lin lunate, the midflle rays more than half length of outer; body 

 rather elongate, the depth (3^) equal to length of head ; eye moderate, 

 3^ in head; dorsal spines moderate, the longest three-fifths head ; pec- 

 torals rather long, three-fourths head ; dorsal rays X, 12; lat. 1. 52. Color 

 silvery, bluish above, with several longitudinal dark stri]3es. 



CALIFORNIKNSIS.t 

 dd. Caudal fin deeply forked, the middle rays scarcely one-third length of 

 the outer ; body not elongate, the depth (2|) much more than length of 

 head; eye very large, 2f- in head ; dorsal spines very high, the longest 

 two-thirds head; pectorals short, two-fifths head; dorsal rays X, 11; 

 lat. 1. 51. Color olivaceous above, silvery below, unstriijed. 



Xenurus. 



* Xeniehthgs xanti Gill, Proc. Ac. Nat. Sci. Phila. 1863, 82. Cape San Lucas {GUI). 



i Xenichthtjs agassizii Steindachuer, Ichthyol. Beitriige, iii, 6, 1875. Galapagos Isl- 

 ands (Steind.). . 



t Xenichthys californiensis Steindachuer, Ichth. Beitr. iii, 3, 1875. San Diego {Steind- 

 achner) ; Cerros Island {Streets', Nichols coll.). 



