14 MUSSEL FAUNA OF THE KANKAKEE BASIN. 



be seen darting in toward the fringes repeatedly. It also probably 

 assists in furnishing fresh water for the respiration of the young 

 mussels. 



At intervals during the undulations small numbers of glochidia 

 are discharged from the brood chambers of the mussel and carried 

 out of the excurrent aperture. These glochidia are of the bookless 

 type, and must be taken into the mouth of the fish that is to carry 

 them during their parasitic period. We can thus understand the 

 advantage of attracting these fish and keeping them in the immediate 

 vicinity during the discharge of the glochidia. 



Since this is the last station before the dredged portion, which 

 includes all the remainder of the Yellow River, we may summarize 

 the results. 



This stretch of river from Plymouth to Ober, a distance of 20 

 miles or more, forms an ideal breeding ground for mussels. The 

 natural conditions are exactly suited to mussel life; there are the 

 right kinds of river bottom, plenty of lime and food in the water, 

 and a current of fairly uniform velocity; the water is kept reasona- 

 bly cool by the springs and brooks which flow into the river, and 

 there are plenty of small fish to distribute the glochidia. 



The river is already well stocked with mussels whose shells are far 

 above the average in size and quality, as can be readily seen by refer- 

 ence to the table of values given on page 39. Furthermore, these 

 mussels are not irregularly distributed in small patches, but form a 

 single bed which is practically continuous for the entire 20 miles. 

 With such natural resources it would be a very easy matter to keep 

 the river stocked with mussels that would yield the farmers a far 

 better revenue than any of the swamp land found in the immediate 

 vicinity. A judicious use of the suppl}^ already at hand, selecting the 

 larger mussels and leaving the smaller ones unharmed for further 

 development, and replenishing the stock regularly by introducing 

 small fish richly infested with glochidia, would insure ample returns 

 for a long series of years. 



The new mussel hatchery just started at Fairport, Iowa, will be able 

 to supply the fish carrying glochidia. Furthermore, the proved 

 quality of the mussels, particularly L. ventricosu^ and L. ligamentin us. 

 would make of this a profitable region from wdiich to obtain glochidia 

 for supplying that same hatchery. The railroad facilities at Ply- 

 mouth, Hibbard, Ober, and Knox are all that could be desired, and 

 there is no trouble in navigating the river between these points in 

 an ordinary rowboat, as was proved beyond question by the present 

 expedition. 



Station 11. Old hed of Yelloio River helow Oher. — No greater con- 

 trast could well be imagined than that which was actually pre- 

 sented between the strip of river just described and that same river 



