20 MUSSEL FAUNA OP MAUMEE KIVER. 



were found: Quadmla rubiginosa, 6; Q. undulata, 60, all rather 

 small; Pleur^ohema clava, 1; Alasmidonta truncata, 2; Symphynota 

 complanata^ 2; S. costata^ 5; Anodonta grandis^ 15; Olovar'ia cir- 

 culus, 4; Lampsilis ligamentinus, 5; L. luteolus, 1; L. ventricosus, 4. 

 This gave a little over 1 shell per square foot. In 1908, in a square 

 meter of bottom near the Rod and Gun Club, the following species 

 were noted : Quadrula rubiginosa^ 9 ; Q. undulata^ 36 ; Symphyiiota 

 complanata, 1; Anodonta grandis^ 17; Obovaria circulus, 11; Lamp- 

 silis iris, 2; L. ligamentinus^ 2; L. luteolus, 3, giving a total of 81 

 per square meter. In addition to these shells there were many small 

 Sphceriums, the ground being paved with them, 34 Campelomxis, 

 and 23 Pleuroceras. The square meter referred to above represents, 

 as nearly as could be judged, an average number rather than either 

 extreme. 



The general impression obtained concerning the abundance of vari- 

 ous species is given in the table on page 37. 



Figure 2, plate i, represents a portion of the dried canal bed near 

 its upper end. It shows admirably the mud cracks formed on drying 

 and the mussel shells still protruding in situ. 



Realizing the value of an opportunity to study so extensive a tract 

 with the mussels still in their original positions and in plain sight, 

 several visits were made to the canal, and as a result the following 

 conclusions were reached : 



1. Each of the species found was well distributed throughout the 

 entire canal; that is, there was no marked gathering together or 

 colonizing of any one species to the exclusion of others. So fully was 

 this true that a careful examination of a few rods of the canal bed 

 anywhere was reasonably certain to yield specimens of all the species, 

 except possibly one or two that were very rare. In this connection it 

 must be kept in mind that the bed of the canal was very different 

 from that of a river, in that it was practically the same throughout 

 its entire length. It was all shallow mud, with little sand or gi^avel ; 

 the water was of nearly uniform depth, and the current was of uni- 

 form rapidity. In short, there was almost nothing except the con- 

 sistency of the mud upon which a mussel could base any preference 

 of locality. Slight differences in this respect caused an increase in 

 the numbers of mussels in some places, but affected all the species 

 equally. 



2. The number of mussels which can find accommodation under 

 fairly favorable conditions upon a definite area in the canal bottom 

 may be judged by the counts on measured areas given above. 



3. A canal makes an excellent breeding gTOund for mussels, as was 

 particularly attested by the presence of a large number of younger 

 examples among the adults, showing all stages of growth. The cur- 

 rent in the canal appears to have been just fast enough, food material 



