244 REPORT OF STATE GEOLOGIST. 



Vigo Couuty {;10, 95); Decatur County (Shauuon). Dr. Jordan (i.^, 

 No. 2, 57) gives it as occurring in Lake Michigan ; Eel River in North- 

 eastern Indiana (4, '94, 38). 



The eel is a resident of both salt and fresh waters. It penetrates to 

 the headwaters of our longest rivers, and when it gets ready to deposit 

 its eggs it goes down again to the sea. The belief now is that it spawns 

 once and then dies. Much remains to be learned concerning the breed- 

 ing habits and the manner of development of the eel. Some investiga- 

 tions have shown that the ovai'ies of a female eel may contain as many 

 as 9,000,000 eggs. The male eel never leaves the salt or brackish water. 

 The young eel reaches a length of about three or four inches at the 

 end of its first year. It is pi-obable that at this time they make their 

 way up the rivers. While living in the sea, eels appear to make migra- 

 tions from one part of the coast to others. On the land they are able 

 to move about on wet grass, and thus they can pass from one stream to 

 another. Eels are extremely voracious, and are the terror of smaller 

 fishes and crustaceans. They go about overturning stones and poking 

 their snouts into every nook and corner, seizing and swallowing their 

 prey. They appear to have a preference for the game iishes. Eels 

 bring a good price in market as an article of food. Their skins also are 

 an article of commerce, being regarded by some people as a remedy for 

 rheumatism 



■ Sub-class 4. PHYSOCLYSTI. 



Primitive skeleton thoroughly ossified. Membrane bones well devel- 

 oped. Body usually covered with scales, which are often ctenoid. Tail 

 homocercal. The vertical fins usually with some spines. The pectorals 

 commonly, but not always, with a spine and five soft rays. Air-bladder 

 of the adult, when present, without a duct. . Veutrals usually thoracic or 

 jugular. The absence of a duct connecting the usually present air-bladder 

 with the oesophagus distinguishes this group from the Physostonn. The 

 characters derived from the nature of the scales, the position and strvicture 

 of the ventral fins, and presence of spinous rays in the dorsal and anal 

 fins, usually, but not always, hold good. We have representatives in 

 our waters of three orders of the sub-class. All of these, with one ex-. 

 ceptioH, have two or more spinous rays in the front of the dorsal. The 

 following analysis of the orders is intended to apply only to our species. 



1. Veutrals abdominal or neai-ly so. Dorsal with two or more spines. 

 2. Dorsal with two or more stiff" and free spines. 



Hemibraitehii, p. 245. 

 3. Dorsal with three or more slender spines in front. 



Percesoces, p. 247. 



