834: Bulletin 47, United States National Museum. 



increased number of ventral rays. In the deep-sea forms the spinous dor- 

 sal is scarcely developed and the scales are usually either cycloid or want- 

 ing. In the species of tropical shores the spinous armature of fins and 

 scales is better developed than in most of the Percomorphous fishes. The 

 group is a very old one in geologic time, the allies of Beryx being among 

 the earliest spiny-rayed fishes known. All are marine fishes, inhabiting 

 the tropical shores or the abysses of the ocean. The pertinence of the 

 Polymixiidw and Mullidw to this group is questionable. 



.Families of BERYCOIDEL 



a. Chin without barbels; ventral rays I, 5 to I, 10; branchiostegals 7 or 8. 



b. Dorsal fin short, single, without spines; ventrals small; subjugular, of 1 spine and 5 

 Boft rays; branchiostegals 7. BATHYCLUPEID^,, cxi. 



bf>. Dorsal fin single, with 2 to 8 slender, graduated spines. Anal spines I to IV; bran- 

 chiostegals 7 or 8. 

 c. Ventral fins subabdominal, each with 1 spine and 5 soft rays. 



STEPHANOBERYCID^E, cxn. 

 cc. Ventral fins thoracic, of 1 spine and about 7 soft rays, (I, 6 to I, 10). 



d. Suborbitals very broad, covering the cheeks. TRACHICHTHYID^E, cxm. 



dd, Suborbitals narrow, not covering the cheeks. BERYCID.E, cxiv. 



"bbb. Dorsal fin deeply notched, its anterior division with many strong spines; anal with 4 

 stout spines; the third much enlarged; bones of head nearly all serrated or spin- 

 ous; branchiostegals 8. HOLOCENTUID^E, cxv. 

 aa. Chin with 2 long barbels, attached just behind symphysis of lower jaw; branchiostegals 4; 



families of uncertain relationship. 



e. Ventral rays I, 7 or I, 6. Dorsal fin single, continuous, with 5 spines ; anal spines 3 or 

 4. Scales moderate, ctenoid; body deep, compressed; vertebrae 29. 



POLYMIXIID.2E, CXVI. 



ee. Ventral rays I, 5; dorsal fins 2, well separated, both short, the first of 6 spines; anal 

 spines 1 or 2; scales large, slightly ctenoid; body rather elongate, the profile para- 

 bolic ; vertebrae 24. MULLID2E, cxvu. 



Family CXI. BATHYCLUPEID^. 



A pneumatic duct to air bladder; ventradiform body, cycloid scales, 

 straightish lateral line, flattish excavated crown, long interinaxillaries 

 extending as far back as the supramaxillaries ; short postmedian dorsal 

 without spines ; long anal with one spine, and small, subjugular ventrals 

 with a spine and 5 rays each. This family shares with the Berycoideans 

 a persistent pneumatic duct. (Gill.) Branchiostegals 7. One genus 

 and two species, in the deep seas. The genus Bathyclupea was placed by 

 Alcock among the Clupeidce, the thoracic position of the ventrals and the 

 shortened abdominal region being regarded by him as a feature of 

 degradation. The species bear, in fact, considerable resemblance to IlisJia 

 and Opisthopterus. (Bathyclupeidce, Gill, in Goode & Bean, Oceanic 

 Ichthyology, 190, 1895.) 



373. BATHYCLUPEA, Alcock. 



Bathydupea, ALCOCK, Ann. and Mag. Nat. Hist., vin, 1891, 130, (hoskyni). 



Head and body compressed ; head with large mucous cavities ; lower 

 jaw prominent. Small, villiform teeth on jaws, palatines, and vomer. 



