426 On a iieio Species q/Lyconns. 



some ])articular3 in a direction coiitnuy to the usual change 

 of developmental proportion. 



A f'urtfier distinction lies in the much longer pectoral fins 

 of L. pinnatus ; while both sjjecimens are too large to be 

 affected by the great development of the pectorals, wiiich is 

 not uncommon in larval Teleosteans, tlie present imperfect 

 state of the type of L. phinatas makes it impossible for us to 

 make an exact comparison of the two species in this respect, 

 though we have no reason to doubt the accuracy of Giinther^s 

 figure. 



The relatively much larger eye of L. pinnatus may be a 

 youtiiful character only, and the present state of the type of 

 that s|)(cies makes any conijjarison of its scale and tin-ray 

 foj'mulie with those of L. brachycolus impossible. 



L. pinnatus has only one canine-like tooth on each side of 

 the vomer; this may be a distinction of importance, because, 

 so far as we know, vomerine teeth tend rather to decrease 

 than to increase in number with age. It has certainly some 

 of the anterior dorsal rays considerably prolonged. la 

 L. brachycolus the first fnir rays are broken, and, though the 

 first ray is slightly stouter than the rest, none of them seem 

 to be stout enough to afford foundation for any considerable 

 production. Moreover, prolongation of the anterior dorsal 

 rays may be a feature of merely sexual importance (cf. Onus 

 cimbrius) . 



The following key should suffice to distinguish the two 

 known species of this genus : — 



LycOxVUS, Gthr. 



1. Head 8 and length to origin of anal fin 3 



times in total length (without caudal) ; 

 pectoral fins longer than (and probably 

 more than half as long again as *) head . . L. pinnatus, Gihr. 



2. Head 5^ and length to origin of anal hu 23 



times in total length (without caudal); 



pectoral fins about § as long as head .... L. brac/ii/colus, H. I't By. 



Rfferences. 



BouLKNGER [1904]. 'Cambridge Natural History,' Fishes, p. (347. 

 G Cn THKii [1887]. ' Challenger " Deep-sea Fishes, "p. I o5. 

 Kegan [1903]. Anu. & Mag. Nat. Hist. ser. 7, xi. p. 4tJ0. 



* See footnote on p. 42."). 



