256 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY - IV. 



ORDER M.-ISOSPOXDYLI. 



(The Isospondylous Fishes.) 



Parietals present. Symplectic present. No interelavicles. A pravor- 

 acoid arch. Anterior vertebrae simple. X< auditory ossicles, IMiaryn- 

 geal bones simple above and below, the lower not falciform. Gills 4, a 

 slit behind the fourth. A very large group, presenting many moditiea- 

 tious of structure. (?TO?, equal ; tfr;>->.i/..<r, vertebra.) 



(riti/KOxtoini (Jiinther. part.) 



ANALYSIS OK FAMILIKS < IV ISOSJ'ONDYI.l. 



* Tail diphycercal. 

 . Lateral margins of upper jaw formed by the maxillar:< ^. 



b. Adipose liu none; no phosphorescent spots; body usually scaly: head naked; 



throat without barbel. 

 c. Lateral line present. 

 </. Gular plate, none. 



<. Air-bladder none; dorsal posterior, opposite anal and similar to if ; mouth 

 small, with small, pointed teeth; deep-sea fishes. 



Al.KI'OCKPIIAI.IIMC, :<!!. 



ee. Air-bladder present : dorsal in front of anal. 



/. Mouth small, horizontal; posterior part of tongue and the roof of I he 



mouth covered with coarse, paved teeth. . . AusrLin.K, :?!. 



ff. Mouth larger, oblique; teeth all pointed; those on the tongne large. 



JIYODONTII'.I.. :!.">. 



dd. Gular plate present ; month large; teeth all pointed ....... KI.OPID.K, :'<">. 



cc. Lateral lino obsolete. 



;/. Mouth terminal, large; maxillary in three parls. mostly liroad. 



gg. Mouth small, inferior; maxillary short and narrow; not in three 

 parts ............................... DOKO.-OMA I II>.K, 38. 



;/.'/.'/ Mouth very large, snbinferior: maxillary very narrow, jiroduced 

 backward ........................... KVCIIAIM ii>n>.i:. :'.'.'. 



bb. Adipose lin present (rarely absent, and the body with plio^phnii-M ml spots*. 

 A. Throat with a long barbel; scales very small or wanting ; mouth 

 large ................................... SK.MIA i ID.I:, !.">. 



lilt. Throat without barbel. 



i. Sides with phosphorescent spots; oviduct* present: deep-sea 



lishes. 



_/. I'seiidobraiH-hiie none ; body scaly ..... < 'n \ i i n n>< >N i n> i :, II. 

 jj. I'seiidolu-anchiie ])resent ; bodymiked . S i i 'i:\. ! i \ . n i i.j . |:1. 

 ii. Siiles without phosphorescent spotaj o\ iducts none. 



SAI.MOMD.; . li'.. 

 aa. Lateral margins ot ii|iper ja\\, like the anterior margin, formed by the pivmax- 



illaries; adipose lin n.-ually present. 



/.-. Pivmaxillaries short, with villiform leeth: month small; 



bone-, o|" head ca\ ernoiis ; s( ales ctenoid . . ]'i RCOPSID^, -17. 



/.A. I'remaxillaries elongad- : month large; bones of head not 



cavernous; scales most l\ cxdoid. 



/. Dorsal short, nearly median: body scaly .. Scon i ID.I:, I'.'. 



//. Dorsal short, posterior: bcidx scaly . I'AKAI r.ri in i>.i , 41. 



///. Dorsal occupying nearly (he whole length of the back; 



body naked ........................ Ai.rnix'-Ai KID.-E, 40. 



