568 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1908. 



Fishes having these characters in common exhibit great diversity in 

 other respects, and not least in the provision for alluring other fishes. 

 They have, however, been mainly associated on account of agreement 

 in other characters. The most essential of these are the position of 

 the branchial apertures, the direction of the mouth, whether opening 

 upward or downward, the number of bones (actinosts) in the false 

 arms (pseudobrachia) that bear the pectoral fins, the development of 

 the first dorsal, and the presence or absence of ventral fins. There are 

 six groups which are so trenchantly distinguished by modifications or 

 combinations of these characters as to have secured from ichthyolo- 

 gists family designations. Their mutual relations may be best 

 exhibited in a synoptical table: 



PEDICULATE FAMILIES. 



I. Branchial apertures about (in or beUiud) the inferior axils of the pectorals; 

 opercular bones moderately or little developed, 



(a) False arms with 2 actinosts; pectorals scarcely geniculated ; 



body depressed; hypapophyses appressed (Lophioidea) 



Lo phi id a: 



( b ) False arms with 3 actinosts ; pectorals strongly geniculated ; 



body compressed or tumid; hypapohyses erect {Antennaroidea) 



Antennariidw. 

 2. Yentrals lost. (Ceratioidea.) 



(a) Mouth large, directed upward; snout flat behind and rostral 



spine erect Ceratiidcc. 



(b) Mouth large, directed downward; snout procurrent and rostral 



tentacle at end and horizontal Giyantactinidcc. 



(c) Mouth small, terminal, and nearly horizontal; snout blunt and 



destitute of tentacle Aoerratiidce. 



II. Branchial apertures about superior axils of pectorals; opercular bones 

 greatly developed ; ventrals developed ; false arms with 2 actinosts ; mouth 

 inferior; rostral tentacle inferior or terminal, sometimes atrophied (Ogco- 

 cephaloidea) Ogcocephalidw. 



Almost all the Pediculates have the foremost spine advanced for- 

 ward near or on the snout and modified to serve as a lure for other 

 fishes ; it has been likened to an angler's rod with its line and bait, and 

 this fancy has been carried out in the names given to the apparatus. 

 S. J. Garman, in his fine work on " The fishes " of A. Agassiz's 

 Reports of an Exploration off the West Coast of Mexico, etc. (1899), 

 has designated as the " illicium " or " bait and rod " the foremost 

 dorsal spine with its leaflike appendage, and further distinguished 

 the " bait " as the " esca." These are developed with various modi- 

 fications in the Pediculates that live in the shallow or less deep seas, 

 and undoubtedly the illicium and esca actually serve as a rod and 

 bait, but, of course, the fish so provided does not knowingly act as an 

 angler, for its action is merely autohiatic. The modification of the 

 spine doubtless originated in a fortuitous manner and its use to the 



