Lake Maxinkuckee, Physical and Biological Survey 433 



"The fine gentleman of the family is the Black-sided Darter 

 (Hadropterus asjjro) . Him we may know by his colors.* The 

 ground hue is a salmon yellow ; the back is regularly and beautifully 

 marbled with black in a peculiar and handsome pattern. On the 

 sides, from the head to the tail, runs a jet-black band, which is 

 widened at intervals into rounded spots which contrast sharply 

 with the silvery color of the belly ; or we may say that on each side 

 is a chain of confluent round black blotches. Sometimes the fishes 

 seem to fade out ; these blotches grow pale and no longer meet, but 

 in an instant they may regain their original form and shade. This 

 latter change can be induced by the offer of food, and it is of course 

 due to muscular action on the scales which cover the darker pig- 

 ment. A male in our aquarium underwent almost instantly an en- 

 tire change of coloration upon the introduction of a female fish of 

 the same species recognized by him as his affinity. Although the 

 two have been together for some weeks, the novelty has not yet 

 worn off, and although his colors vary much from one hour to 

 another, he has never yet quite reverted to his original hues. The 

 form of the Black-sided Darter is more graceful than that of 

 any other, and his movements have little of that angular jerki- 

 ness which characterizes his relatives. The fins of Hadropterus, 

 like those of Percina, are long and large, the number of dorsal 

 spines being about 14. A notable peculiarity in both species is 

 the presence of a row of shields, or enlarged scales, along the 

 middle line of the abdomen. These may help to protect that part 

 from the friction of the stony bottom. They seem to be shed some- 

 times, but when or why this happens we do not know. Hadi'op- 

 terus delights in clear running water and may be found in most 

 streams south and west of New York. It is especially desirable 

 for aquaria, being hardier than any other fish as pretty, and 

 prettier than any other fish as hardy, and withal with 'a way of 

 his own,' as an Irish laborer, Barney Mullins, once said to us of 

 Thoreau." — Jordan and Copeland. 1876. 



57. DUSKY DARTER 



HADROPTERUS SCIERUS Swain 



No specimens seen in the lake ; found only in Outlet Creek 

 below Lost Lake. 



Attention has already been called to the close relationship of 

 this species and the preceding, and to the probability that they are 

 connected by intermediate forms. This opinion is the result of an 



* This is no lonccr the case since H. scicrus and //. iiia.ii)tl:iickicttsis have been described. 



