o2 THE AMERICAN MIDLAND NATURALIST 
From the data presented under the title of each area, the 
following tabulation is made, dealing with the absolute 
abundance of shells in the areas appraised: 
No. Shells No. Shells 
pceeud Commercial Species Non-Commercial pee 
Status as to nee Species per Shells per 
iguery Linear Mile Linear Mile tra 2 
iOpen ses aes 197.1 66 263.1 
ii Closed 3 = 84.1 47.9 131.5 
IieeOpen! 22 222— 39 5.61 44.61 
LV. Closed) 22-2 92 10.3 102.3 
WeOpen 22>." 2 166.8 7 173.8 
Wiis Closed: +22 2-3 243.25 ; 15.5 258.75 
MIT Open. oe: = 14.5 (16.13) 1 (6.55) 15.5 (22.68) 
WATT Closed 2 == 10. (48 1.2 (2.8) 11.2 (45.8) 
Px Opent 2 28.24 (54) 4.76. (7.6) 33. (61.6) 
Xe. Closed 2. 45.3 (62.91) 4 (8.3) 49.3 (71.24) 
In the preliminary report of this survey, (p. 2) the data 
_ given on the absolute abundance of shells in Areas VII-X 
inclusive, was based in large part on collections of shells 
by hand from sand bars, as the latter embraced the larger 
number of best localities in the areas indicated. As it would 
be difficult to use such data in the future as a basis of com- 
parison and rechecking, there has been substituted in this 
final report data obtained from other localities in these areas 
by the use of the bar and crowfoot outfit. Since it is felt 
that, due to the conditions described, that the latter represents 
the true absolute abundance of shells in the areas, there are 
added in parentheses to the above the results obtained from 
collecting by hand on the 3 best sandbars of these areas. For 
each of the 3 localities taken in account for each area, the . 
data thus presented embodies the efforts of 3 men collecting 
by hand 30 minutes, a total consumption of 90 minutes time, 
and about that required to make 3 drags with the bars in any 
given locality. The results from the sandbars may be inter- 
preted to represent the maximum of shells in the particular 
area. 
VII. REMARKS AND RECOMMENDATIONS. 
The tables given indicate that commercial species of mus- , 
sels in the areas appraised are most abundant in the vicinity 
