148 Illinois State Lahomtorij of Natural Ilistonj. 



seen measured 6 inches in length, and the hirgest 12.25 inches. 

 This last was the only one taken that had lost the caudal fila- 

 ment. The more uniform occurreiice o£ this gar in bottom- 

 land pools of all sorts and its greater abundance there, in addi- 

 tion to the smaller average size of the young as compared with 

 those of L. platysfonms, suggest a later spawning time. If the 

 short-nosed gar spawns earlier, its young have more time to es- 

 cape from the temporary pools, and we should expect to find 

 fewer of them present in August. The matter needs further 

 attention, however, as adifEerence in the relative abundance of 

 adults in the river at this point, or some unknown difference 

 in spawning habit, may have to do with some of the differ- 

 ences we have noted. 



Localities: Harkness Slough, Dead Man's Slough, Moss 

 Lake, Claus Lake, Willow Slough, Lily Lake, Long Lake, Broad 

 Lake, Wood Slough. 



Famidy Poltodontid^. (Shovel-fish.) 



Shovel-fish {Polyodon spafhula, Walbaum.) 



This fish evidently does not spawn on the overflowed bot- 

 tom-land. A single example about 14 inches long from Wood 

 Slough was the only one taken. The adults are common in 

 the Mississippi River, where they were occasionally seen leap- 

 ing above the water. 



Family Petromyzontid^. (Lampueys.) 



Lamprey Eel ( Petromyzon castaneus, Gir. ) 



A lamprey taken by the men from Wood Slough was prob- 

 ably of this species. It was not secured for examination. 



INVERTEBRATES. 



Small animals, such as insects, crustaceans, and mollusks, 

 were not as abundant as they commonly prove to be in jierma- 

 nent bodies of water in other localities. The absence of vege- 

 tation and the abundance of their enemies, the fishes, doubtless 

 both had to do with this. The condition of these pools, as we 

 have seen, is not favorable to a growth of vegetation, and the 



