GILBERT AND STAKES — FISHES OF PANAMA BAY 103 



i86. Lutianus argentiventris (Peters). 



With the exception of L. guttatus, the most abundant species of the genus. 

 The species is marked by the very slender sharp snout, the profile being concave in 

 front of the nape, convex behind it. The snout is three-eighths to four-elevenths 

 the length of the head, and equals the length of the maxillary; it is not depressed 

 anteriorly. The blue stripe below eye is conspicuous only in the young. It may 

 extend, without interruption, from the tip of the snout along entire side of head to 

 opercular margin. It is more often limited to the anterior part of the head, and 

 becomes variously broken up into a series of dashes or dots. 



187. Lutianus Colorado Jordan & Gilbert. 

 Not abundant; reaching a large size. 



188. Lutianus guttatus (Steindachner). 



The most abundant species of the genus; never reaching a large size. This 

 species has the temporal region more extensively scaled than in other American 

 representatives of the genus in the Pacific. The usual temporal band of large scales 

 is present, in addition to which are bands of small scales in front of and behind it. 



189. Lutianus aratus (Gi'mther). 



Less abundant than other species of the genus; several specimens secured. 

 The maxillary reaches past the middle of the eye. 



190. Rabirubia inermis {Peters). 



A single mutilated specimen was found. The species must be one of the 

 rarest known, as but three specimens have been noted by collectors. The figure 

 published by Jordan (Proc. Calif. Acad. Sci., 2nd Ser., Vol. V, 1895, Plate XXXIX), 

 errs in the number and obliquity of the dark streaks above the lateral line. Nineteen 

 or twenty of these can be distinguished on the specimen from which the drawing 

 was made, and the streak from last dorsal spine runs to the tenth scale of the lateral 

 line. The anal fin contains ten rays in each of the Panama specimens known. 



191. Xenichthys xanti QUI. 



Brought to market in abundance. The best description of this species is that 

 given by Jordan and Gilbert (1882 a, p. 325) under the name of X xenops. The 

 following details may be added. 



Eye 3 to 3| in head. Scales 52 to 5-4; those on head and nape less coarsely 

 ctenoid than elsewhere. The fourth dorsal spine is as long as the third, or some- 

 times a little longer; the fifth is but slightly shorter. In the declined fin, the fifth 

 spine reaches past the tips of all the other spines anterior to the tenth; the pectoral 

 does not reach the vertical from the vent. In the six specimens counted, the dorsal 

 was constantly XI, I, 18, the anal III, 17. 



