1772 Bulletin //, United States National Museum. 



ee. Lower jaw much projecting ; head broad, skull usually convex ; 

 cranial ridges when present usually low. Gill rakers very 

 long and slender; scales usually smooth, few, if any, acces- 

 sory scales. Branchiostegals and lower jaw scaled. Pores 

 of lower jaw concealed except in some species of Acuto- 

 mentum. 

 /. Preocular spines well developed. Peritoneum black. 



g. Postocular spine present. Supraocular, tympanic, 

 and occipital spines well developed. Second anal 

 spine stronger and usually longer than the third. 

 Symphyseal knob strong, projecting forward. 

 Dorsal low. Lower pectoral rays normal, not 

 thickened. No spines on inter- and subopercles. 

 (Mandible and maxillary scaled.) ACUTOMENTUM. 

 gg. Postocular spines not developed. Supraocular and 

 tympanic sometimes present, always concealed 

 by the skin. Occipitals ending in spines or not. 

 Tnterorbital wide, convex. Lower pectoral rays 

 thickened, their tips projecting beyond the mem- 

 brane. Bones of the skull striate and pitted. 

 Mouth small, narrow. Spines on inter- and sub- 

 opercle sometimes present. Peritoneum black. 



PBIMOSPIKA. 



ff. Preocular without spine; skull smooth, without spines. 

 Lower pectoral rays normal. No spines on inter- or 

 subopercle. Peritoneum usually white. 



SEBASTOSOMUS. 

 dd. Parietals separated by the supraoccipital.* 



h. Cranium with parietal ridges only. Lower jaw much project- 

 ing, entering the profile; a prominent symphyseal knob 

 directed forward. Head broad, convex. Interorbital con- 

 vex, nearly smooth. Lower pectoral rays normal; no 

 spines on inter- and subopercle. Exposed branchiostegals, 

 maxillary, and mandibles densely scaled. Pores of lower 

 jaw concealed by the scales. SEBASTODES. 



hh. Cranium with many ridges, all ending in spines. Branchios- 

 tegals (except in A. aurora, S. proriger, and S. rufus) and 

 usually the lower jaw naked. Pores of lower j aw, except 

 in Auctospina, very large, conspicuous, slit-like. 

 i. Postocular and tympanic spines both present. Lower 

 pectoral rays thickened (except in Sebastomus rufus). 

 Interopercle and subopercle usually with spines. 

 j. Coronal and nuchal spines present; a spine below, 



another in front of eye. ( ). 



jj. Coronal spines not developed. SEBASTOMUS. 



ii. Postocular spine not developed; iuteropercle and sub- 

 opercle each with a spine at their approximated 

 corners. 



fc. Coronal spines not developed.; lower pectoral rays, 

 usually thickened ; interorbital usually with 

 a groove in its middle. The large pores (4) 

 along each ramus of the lower jaw open. Max- 

 illary, mandible, and branchiostegals usually 

 naked or with minute embedded scales. 



PTEKOPODUS. 



* Except in cereus and sometimes in elongatus. 



