334 Dr. Chr. Liitken on Oneirodes Eschrichtii, 



the channel between the forehead and the skin which serves 

 as its bed : the uppermost part of the head (fig. 2) is white 

 (colourless), with a sharp limit, and thus contrasts strikingly 

 with the otherwise black colour of the fish ; it is, moreover, 

 furnished with several fine processes resembling tentacles, and 

 with some pigment-spots, the distribution and other peculiari- 

 ties of which will be better un- 

 derstood from the figures and 

 detailed description : here it may 

 be sufficient to state that, on 

 the upper surface of the clavate 

 head there are first three short 

 filaments (fig. 2, a) with black 

 tips, placed before and below 

 the base of a black tubercle {h), 

 and behind and below the lat- 



Fic 



ter and a lower light-coloured 

 tubercle (c) two similar but 

 much smaller tentacles {d). At 

 the posterior end there is also 

 a strong tubercle {e) with a 

 black apical sm-face, and behind 

 and below this a tolerably long 

 tentacular filament, thin and 

 fine towards the apex and thick- 

 ened at the base (/): and in The clavate head of the frontal ray, 

 ,, . , Ti i> ,, w/' seen trom above and Irom the Side, 



the middle ol the upper surface enlarged. 



of the clavate head a trans- 

 verse series of four fine tentacular filaments {g), two longer 

 ones in the middle and a shorter one on each side, which might 

 be described as bifid or furnished with a shorter lateral branch, 

 if the two on the left side did not differ in having the inner 

 one simple and the outer, in compensation, trifid. Both these 

 and the unpaired hindmost tentacular filament are destitute 

 of the black pigment which characterizes the foremost set*. 



* I am, of course, not in a position to indicate the purpose of this sin- 

 gular structure ; but I will not conceal that the whole arrangement has 

 above all produced a " mimetic " impression upon me, as if it vrere in- 

 tended to resemble, e. y., the head of a Nereid ; and I haVfe been compelled 

 to think of the old notions of the employment by the fishing-frog of its 

 homologous frontal appendage as a means of attracting other fishes, 

 which, indeed, have given origin to its scientific specific name (however 

 little we can place unconditional confidence in them). 



I may admit that hitherto I have paid no particular attention to the 

 conjectures that the tentacular filaments, barbels, &c. of various fish are 

 employed merely as a means of attracting smaller fish of prey by their 

 resemblance to worms playing in the water ; and it is therefore very pos- 

 sible that positive obsen'ations in this direction may have escaped me. 



