18 SMITT, ON THE GENUS LYCODES. 



traces of a median lateral line may be seen, just as in tlie 

 reticulatus-gTow]) a dorsal line may be added to the median 

 one. Now it happens also, that sometimes (see f. i. in N:o 

 V. 34 in our tables of measurements) all the three lines are 

 present, although, as far as we have seen, in a rudimentary 

 state, with the scattered pores visible only as small, white 

 döts. Very of ten, most frequently in old specimens, and al- 

 ways in the youngest, the lines are indistinct, in such a 

 degree that they scarcely may be perceived, thus making the 

 cited character useless. It is a very ambignous character, 

 but may sometimes be iised as a supplementary one; and as 

 it unites the frigidus-form. with the Valdii- grou-p, although 

 that form in other respects is a trne reticiilatus, it will 

 strengthen the above made supposition that hybridism has 

 played its part in the origination of the frigidus-torm. 



Lately (1898^) it has been suggested that one of the most 

 striking characters would be derived from the breadth of the 

 pectoral fins. This we have tried to pro ve by measuring 

 the height of the base of these fins {2)h), which in our speci- 

 mens we have found variable enough, from about 4\/3 or 4 

 to 7V2 or 72'3 per cent of the total length of the body, thus 

 very well suggesting the probability of its giving place even 

 to any specific distinction. But the figures, as may be seen 

 already from our tables of primary per cent figures (tables 

 II and III), are very irregular, although within the respective 

 groups increasing in the main with the age of the specimens, 

 what in the average-table (table IV) is expressed also by 

 their steady increasing in the form-series from gracilis to 

 reticulatus. As in the first-named table they cross över each 

 other, from the one form to the other, they can not give us 

 any constant characters for the respective forms; but their 

 auxological changes through their regularity in the averages 

 give US a new proof of the correctness of our views of the 

 natural relations between the species, forms and varieties. 



This will be still more evident by comparing the breadth 

 of the base of the pectoral fins with another part of the body, 

 as f. i. the length of the tail. 



^ JoEDAN and EvERMANN, Fish. North a. Mid. America, p. 2462, note. 



