390 BEVISION OF SEBASTIN.¥.—EIGENMANN AND BEESON. vol. xvii. 



determination of its generic relationships to some one who lias speci- 

 mens. 



VIII. GENUS SEBASTOMUS, Gill. 



Sehastomiis, Gill, Proc. Acad. Nat. Sci., Pliila., 1864, p. 147 (rosaceusj. 



Type. — SehaMes rosaceus, Girard. 

 The species of this genus are all closely related. The armature of 

 the skull varies but little. 8. ruber, with broken cranial ridges, stands 

 at one extreme, S. levis at the other. The bulk of the species have sev- 

 eral pale spots on the sides which are siiiularly arranged in the difier- 

 ent species. 



ANALYSIS OF THE SPECIES OF SFBASTOMUS. 



a. Cranial ridges cutirc. 



h. Median portion of interorbital with a convex ridge. Cranial ridges low, bones 

 of craninm striate orgrannlar; symphyseal knob project- 

 ing nearly as in Schiisfosomus flaridus ; second anal spine 

 little longer or stronger than third, 

 c. Gill-rakers very long, 1^ in orbit ; scales all ctenoid. 



d. Supraocular, postocular, and tympanic spines tubercular or pyramidal, 

 very broad and short, directed upward more than back- 

 ward. Dorsal spines 2| in head. Syraphyseal knob very 

 sharp. Numerous accessory scales above lateral line and 

 on tail. Anal spines graduated, slightly more than 3 in 

 head. Outlines of spinous dorsal little arched. Com- 

 pressed, elongate. Maxillary reaching to middle of eye. 

 Interorbital slightly convex, as wide as orbit or little 

 wider. Eye longer than snout 3A-4 in head. Preorbital 4 

 in orbit, with 2 small, backward directed spines. Head 

 entirely covered with moderate-sized scales, body with 

 larger ones. Rufous, variously marked with brown. 

 Lateral line rufous. Upper angle of opercle, a line from 

 eye to upper half of pectoral, another parallel to it from 

 upper angle of niaxilhiry backward, and tips of jaws 

 dark brown. Axil black. Margin of spinous dorsal and 

 greater part of membranes of soft dorsal black. Caudal 

 dusky. Membranes of remaining lius chiefly black. 

 Head 3; depth 3i: D. XIII, 14; A. Ill, 8. Tubes in lat. 1. 



56 RUFUS, 1. 



dd. Supraocular, postocular and tympanic spines all slender, conical, their 

 acute tips directed backward more than upward. Dorsal 

 8pinesabout2irin head. Symphyseal knob blunt. Acces- 

 sory scales few. Head broad, the interorbital 3 in the dis- 

 tance from tip of snout to base of occipital crest. Man- 

 dible, maxillary, and tip of snout scaly. Membranes of 

 spinous dorsal not greatly incised, 



e. Scales of mandible very rough; color chiefly brick red miniatus, 2. 



ee. Scales of mandible smooth ; color chiefly orange pinnigkp, 3. 



cc. Gill-rakers short, not more than three times as high as Avide. Scales of head 

 cycloid, those of body weakly ctenoid; accessory scales 

 numerous. Head narrow, the interorbital 4f in the 

 distance from tip of snout to base of occipital crest. 

 Mandible, maxillary, and tij) of snout naked. Highest 

 dorsal spine little less than half length of head, the mem- 



