340 Dr. Chr. Liitken on Oneirodes Eschrichtii, 



unquestionably are, presenting a certain difference in the size 

 and direction of the mouth, in the strength of the dental ar- 

 mature, in the number of fin-rays, &c. &c. ? And in this 

 whole group are not the number and development of the free 

 dorsal fin -rays so different and so variable that it would be 

 less natural to lay so great a stress upon the differences of the 

 two fishes under consideration in these respects ? 



I will not here insist that in any case it would be necessary 

 to alter the generic characters of Melanocetus considerably in 

 order to make a place for the Greenland species within its 

 boundaries, because I feel so much less inclination to under- 

 take any such alteration of the definition originally given for 

 that genus, as I have not been able to lay together side hy 

 side the forms in question, and thus to weigh similarity and 

 dissimilarity in the fine scale of direct observation ; but to this 

 hesitation we might in general only concede a subordinate and 

 merely subjective importance. What appears to me to settle 

 the question of the relation of Oneirodes to Melanocetus is the 

 relation of both to Ceratias ; for under all circumstances it is 

 evident that Oneirodes [Eschrichtii) will have its natural place 

 between Melanocetus {Johnsonii) and Ceratias {Holbolli) , cer- 

 tainly much nearer to the former than to the latter, but yet 

 distinctly pointing from the one to the other ; and this to a 

 certain extent intermediate position must receive its most 

 adequate expression by proposing to elevate the new form into 

 the type of a distinct genus. I therefore entertain but little 

 apprehension that future investigations of new intermediate 

 forms should cause its abolition. As the facts stand now, 

 it seems to me that Oneirodes has not merely a formal right 

 to stand over against Melanocetus, but also a real, or, if you 

 will, an ideal one ; Melanocetus is a not much less extravagant 

 modification on one side of the common trunk-form (to adopt 

 the speech of recent times) which we may here suppose repre- 

 sented by Oneirodes, than Ceratias is on the other. Between 

 all these there is the nearest affinity ; and they seem to form a 

 very natural little group of deep-sea Lophioids, of weak vision 

 and destitute of ventral fins, within the great family of the 

 Halibatrachi. This group is again divided into two — the 

 smooth, naked-skinned forms ( Oneirodes and Melanocephalus) 

 and those with bony tubercles in the skin {Ceratias and Hi- 

 mantolophus) . 



Ceratias and Oneirodes, indeed, are not the sole representa- 

 tives of the Lophioids, and especially of the subdivision of 

 that family here under consideration, in the deep seas off the 

 Greenland shores. There is also here a third form, whicli the 

 elder Reinhardt described under the name of Ilimantolophus 



