170 



LOWER VER TERRA TES. 



These are greenish in color, and banded or reticuhited, rather than spotted, and, in all, 

 the opercles as well as the cheeks are fully covered with scales. One of these {Esox 

 reticulatus) is the common pickerel of the Eastern States, which reaches a respectable 

 size, and is excellent as food. The others {Esox americaniis, Esox vermiculatus) 

 seldom exceed a foot in length, and have no economic impoi-tance. 



Closely allied to the Esoeid.'e is the small family of the mud-minnows, or Umbrid^, 



which technically differ from the pike, 

 chiefly in the smaller mouth and weak 

 dentition. The two known species reach 

 but a small size, and their distribution is 

 somewhat anomalous, indicating perhaps a 

 former wider range. 



The species are sluggish, carnivorous 

 fishes, living in weeds or mud at the bot- 

 toms of clear streams or jwnds in rather cold regions. Tliey are very tenacious of life, 

 but do not live long in warm or turbid waters. 



Of the known species, the Hundsfisch ( Umbra crameri) is found in Austria. Its 

 near relative, the mud minnow ( Umbra Kmi) abounds in the streams and swamjjs 

 of the northern states. It often lives for a long time imbedded in the mud of prairie 

 sloughs and bog-holes, where it has sometimes been ploughed up alive. 



The large family of Ctpbixodontid^ or killiiishes, is distinguished among the 

 Haplomi l)y the structure of its mouth. The short ujiper jaw is extremely protractile. 



mud uuiinow. 



Flii. IIM. — Anableps telrophthalmus. 



and its margin is formed by the premaxillaries alone. The teeth are small; and of 

 various forms. The scales are large and cover the top and sides of the head. The 

 stomach is without pyloric coeca, and the intestines are long or short according to the 

 food of the fish. 



