6 SMITT, ON THE GENUS LYCODES. 



4 specimeiis of Lycoäes (Lycenchelys) murcena^ as well as of 

 17 specimens of L. Sarsii,^ we find that the relative length 

 of the liead in this subgenus is normally diminishing from 

 the young to tlie old age; but in the true Lycodes, setting 

 aside the larval stages (fry, with a length of the body less 

 than 60 millimetres), we find that length of the head nor- 

 mally increasing with age. The two subgenera then seem 

 to have started from the same origin, developing themselves 

 in opposite ways. 



As to the true Lycodes, between the cited 6 forms in the 

 individual per-cent numbers we find no constant difi^erences, 

 but in the average-numbers (see Table IV) the figures are 

 rather regularlj- increasing from the Vahl/i-growp to the 

 reticula tus- gr on^. Thus the former group seems to represent 

 the lowest stages of development. The least figures we find in 

 Lycodes gracilis; but it may perhaps be questioned, if that not be 

 a consequence rather of degeneration (regressive development) 

 than of originality. In the most instances the males have 

 greater figures than the females; but this sexual difi'erence 

 is not constant, what will most easily be seen from the 

 averasres: 



Averages 



gracilis^ 



cT 



pallidus I Vahlii 



I ef 



ef 



frigidus 



& 



semi- 

 nudns 



ef 



reticii- 

 latus 



ef 



a: mm. 



b/a % ■ 



(140.2) 

 (19.9) 



(144.5)93.6 106.5 

 (19.7),20.9| 22.5 



137.3206.2 

 21.8 23.0 



244.2 145.2 140.9 

 24.9 24.5 25.5 



189.7 

 27.3 



95.3150.1 

 24.7 25.9 



The difi'erent parts of the head {h^; h^; hp'. c; e; g; </, ; 

 h; Jc: h', as well as Itc and Itb) present the same evolution al 

 changes as well in the ontogenetic development as in the 

 form-series, and that sometimes with such a regularity, that 

 f. i. the specimens of pallidus m2ij be divided in two groups, 

 the younger {a < 99 mm.) with the upper jaw {ha "^ less 

 than 9 °o and the lower jaw (ä; „ %) less than 11 % of the length 



1 Norsk. Nordh. Exped., Zool., Fiske, p. 119: 



a (millim.) 



b a % 



112 

 14.3 



141 

 12.9 



198 

 12.6 



217 

 12.0 



2 Cfr. Ann., Mag. Nat. Hist., ser. 7, vol. V, p. 58. 



^ The figures in brackets are no true averages, because we have not 

 more than two males and two females of this form. 



k 



