DISCUSSION OF SPECIES AND THEIR DISTEIBUTION. Sf) 



b. Dorsal short, postmcdian. Scales thin, caducous PaI!alkpi1)II).t-: 



c. Dorsal short, median. Body naked Oddxtostomih i-; 



»• Vertebrae normal. Anterior neural spines abnormally developed, projecting through the skiu of the 



back, In advance of the dorsal. 

 1. Body compressed, ventradiform, carinated. 



a. Mouth obliquely cleft, or subvertical Stkk.noptvciiiii.e 



*»* Vertebra' with spiny processes anteriorly which i)rojeet through the skin of the back in front of dor- 

 sal rays. 



1. Pectorals alisent. Body elongate. 



a. Body naked. Dorsal beginning in advance of the vent Ll>laca>tiiidj£ 



Family ALEPOCEPHALID.^. 



Alepocephales, Cuvier & Valenciennes, Hist. Nat. Poiss., xix, 169. 



Alepoccphalida; Eichaedson, Encye. Britannica, 8th ed., 1856, 255.— Gunther, Cat. Fish. Brit. Mus., vii, 



1868, 477. — Gli-i., Arrangement, Families of Fishes, 17. — Jordan and Gilbert, Bull, xvi, U. S. Nat. Mu.s., 



257. 

 Alepocephaloidei, Bleeker, Enum. Spec. Pise. Aich. lud., 1859, xxx. 



Malacopterygians witli body more or less compressed, covered •with thin cycloid or keeled 

 scales, or with naked, jjiiekly skin. Head naked. No barbels. Mouth moderate or large, 

 the margin of the upper jaw formed by the x)remaxillaries and mamillaries, the former i^lacetl 

 along the upper anterior edge of the latter. Opercular apparatus complete. Teeth feeble. 

 No adipose tin. Dorsal flu loug and low, posterior, inserted opposite the anal; pectorals 

 short, placed rather high; veiitrals usually well back, sometimes wanting. Pseudo- 

 branchi;e present. No air bladder. Stomach curved, Avithout blind sac. Pyloric cceca in 

 moderate number. Gill opeuings very wide. 



KEY TO THE GENERA OF ALEPOCEPHALID^. 



I. Body covered with scales. 



A. Ventrals iireseut. 



1. MaxiUaries toothless; mouth of moderate width ; scales thin, cycloid. 



a. Dorsal and anal similar and nearly equal; body oblong ALEPOCEPHALr.S 



b. Anal nmcb longer than dorsal ; body elongate C'onocara 



3. MaxiUaries toothed; mouth wide. 



a. Gill openings narrow, teeth in premaxilla and mandible uniserial Batiiytroctes 



b. GUI openings wide, teeth in premaxUla and mandible pluriserial Narcetes 



B. Ventrals absent; scales small, keeled; body abbreviated, high, much compressed PLAiVTHotTES 



II. Body scaleless. 



A. Dorsal normal, equal in length to anal; scales replaced by nodules. 



1. Lateral line present Xenodeemiciithys 



2. Lateral line absent jVleposo.mis 



15. Dorsal normal, shorter than anal Leptodekma 



C. Dorsal preceded by a long adipose fold ^\_Nu.MAiOPTERCS 



III. Body with minute, hardly imbricate scales. 

 A. Pseudobranchiie quite rudimentary. 



1. Bones of the head produced in a long snout Ailosto.mati imorph a 



ALEPOCEPHALUS, Risso. 



Alepoceplialus, Ri,s.«0, Mem. Accad. Nat. Sci. Turin, xxv, 1820, 270.— MCi.ler, Abhandl. Akad. Wiss. Berlin, 

 1846, 171.— CrviKRand Valenciennes, Hist. Nat. Poiss., xix, 169.— Gcntiikr, Cat. Fish. Brit. Mus., 

 vii, 477. — Jordan and Gilbert, Bull, xvi, V. S. Nat. Mus., 257. 



Body oblong, compressed. Jlouth moderate, the snout somewhat prolonged. Jaws 

 neai-ly even in front; a series of small teeth in each jaw and on the vomer and palatines. 

 Eye very large. Gill membranes entirely separate. Branchiostegals (>. Opercular bones 

 thin. Dorsal low and rather long, with a scaly base, opposite and similar to the anal. Pec- 

 torals and ventrals rather small. Caudal moderately forked. Scales rather large, thin and 

 cycloid. 



