!4 IA'CODIN.E. 



carried out 1>\ Dr. C. G. Job. Petersen and Dr. Johan Hjort in 1897—98, a very large number of individuals was taken 

 in the Kattegat, Skager Rak and Christiania Fjord. Based on this rich material, Prof. R. Collett published in 1899 a detailed 

 description with numerous figures of the species and of its changing appearances from the young stages up to the reproduc- 

 tive period, the latter stage being reached in these waters at a length of 125 -150 mm.; the largest specimen was 178 mm. 1 ) 

 During the same period, the geographical distribution of this species became widened to embrace Iceland and West Greeu- 

 land 2 ); Collett had obtained from Iceland in 1891 a young specimen from B. Groudal of Reykjavik, and the Ingolf expedi- 

 tion took 2 specimens 143 and 244 mm. long in Davis Straits in the summer of 1895; the last specimens were determined 

 by the present author as L. gracilis and were published under this name in the report on the ichthyological results of the 

 Ingolf expedition il.utken I.e.). 



Prof. Collett in the same treatise, examined the relation of L. gracilis to allied species. Lack of sufficient material 

 obliged Collett to leave unsettled whether or not L. gracilis is identical with L. rossi Malmgr. and L. pallidas Coll., both 

 known from Spitsbergen. Further it is possible, he states, that L. gracilis may be shown to grow elsewhere to a greater 

 size and be identical with some earlier described form, whose young stages are as yet unknown. 



On the first possibility, I am unable to give Prof. Collett any support, as L. rossi is in all probability the young 

 stage of another species (= /.. cclalits mihilj) and L. pallidas is a good species as I shall show later. 



On the other hand, L. gracilis is in my opinion identical with the species long known from Greenland 



which Reinhardt (sen.) set up as the type of the genus, namely L. valiliU). Our Museum possesses half a score of 



specimens of this Lycodes, and 7 of these were examined by Reinhardt and Liitken whilst 3 are of more recent date 



[885); the value of the material is diminished by the bad preservation of the specimens on the whole, but it is quite sufficient 



to sustain the certainty of the contention here set forth. 



Further, I am in a position to furnish proof that the L. lugubris from Iceland (Ofjordl, described by Liitken 

 in 1880, must also be referred to L. valilii. 



We see therefore the peculiar phenomenon that one and the same fish has been ascribed to 3 different species, 

 according as it lives in the waters of Scandinavia, Iceland or Greenland. The reasons for this are twofold: partly because 

 the separate authors have had only a limited material to decide upon; partly because the specimens fall into three groups, 

 which severally present certain differences, and each of these groups possesses its own geographical and separate region. 



As a contribution to the knowledge of the importance of geographical elements 5) for the formation of separate races 

 the present example is not without interest, and we shall therefore look into this point a little closer later |p. 191. 



I shall proceed now to treat of the separate forms, employing as titles the names they have hitherto borne. 



Lycodes gracilis M. Sars. 

 The form from Scandinavia is so well known from Collett's latest researches (1S99) that I 

 need not dwell upon it. Collett's treatise I shall suppose as known in the following pages. 



Lycodes vahlii Reinhardt. 



Tab. I, Fig. 2 a, 1). 



At the time when I was assisting Prof. Liitken with the revision of the manuscript of The 

 Ichthyological Results of the Ingolf Expedition, I saw that two small Lycodes, taken in Davis Straits 

 out from Sukkertoppen in 88 fathoms, must be ascribed to L. gracilis with which I was familiar 

 through the numerous specimens from the Skager Rak presented by Dr. C. G. J oh. Petersen to the 

 Zoological Museum. Prof. Liitken sent these two specimens to Prof. Collett who was then busy with 

 his monograph on Z,. gracilis ; Prof. Collett acknowledged the correctness of the determination and 

 has mentioned the discovery in his treatise. 



At the same time, subjecting the other preserved material in the Museum of Lycodes from 

 Greenland to a hast)- review, it struck me that the youngest of the specimens labelled under the 



'I A somewhat larger specimen, 196 mm. long, was taken later (1900) in the Gullmar Fjord (Bohuslan); it is preserved 

 in the Riks-Museum at Stockholm, where I have had the opportunity of seeing it. 



2 ) By an error in writing Collett has East-Greenland (I.e. p. 8). 



3) Later: A rich material recently obtained has made it clear to Prof. Collett also that I. rossi is an independent species. 



II It might appear as if Prof. Smitt had already published a similar opinion, but his L. vahlii is uot the same as 

 /.. vahlii Reinhardt See further p. 15, note 1. 



5) By geographical elements I understand the sum of the natural conditions in the region. 



