APPARENTLY CORRELATED TO THE CONDITIONS OF LIFE. 
329 
Table Showing the Comparative Weights of Shells of Similar Size. 
For the purpose of this Table twenty shells were chosen from each sample to be 
compared, as nearly alike in length as was possible. 
The first column gives the name of the locality, the second the level, the third 
shoM's the extremes of length in millimetres of the shells selected, the fourth column 
gives the sum of the lengths of the twenty shells, and the fifth column gives the total 
weiofht. 
Locality. 
Level. 
Extremes of 
lengtji in 
millimetres. 
Average 
length of 20 
specimens. 
Total weight 
in grammes of 
20 .specimens. 
Shore of Aral Sea. 
21-17 
19-2 
1 
13-3 
Shumi.sli Rul. 
First terrace . 
21-17 
19T 
14T 
,, . . 
Second terrace . 
21-17 
19-4 
14-5 
Fourth ten'ace . 
21-17 
19-2 
6-5 
Fifth terrace . 
21-17 
18-9 
6T 
. 
, Shore of Abu Kir. 
Seventh terrace . 
21-17 
19-7 
4-6 
21-17 
19-0 
6-4 
Jaksi Klich . ■. 
Upper deposit . 
23-19 
20-4 
7-8 
1 ')•> .. 
Ijower deposit . 
23-19 
20-4 
5'5 
1 Jaman Klich. 
Lower deposit . 
21-17 
19-2 
5T 
Ancient shells exposed at Manclara . 
26-21 
23-4 
24-2 
' Shore of Mareotis. 
25-22 
23-8 
12-0 
Ramleh Lake No. 1 (fresh-water) . 
25-20 
21-4 
18-3 
Ramleli Lake No. 2 (fresh-wateip . 
26-23 
24-1 
23-6 
1 
Explanation of Plate 26 . 
Figs. 1-7 represent shells of Cardium edule from the successive terraces at 
Shumish Kul. 
Fig. 1. Eight valve from the first {i.e., the highest) terrace. 
Fig. 2. Eight valve from the second terrace. 
Fim 3. Left valve from the third terrace. 
o 
Fio'. 4. Eicjlit valve from the fourth terrace. 
Fig. 5. Eight valve from the fifth terrace. 
Fig. 6. Eight valve from the sixth terrace. 
Fig. 7a. Left valve from the seventh terrace, seen from the outside. 
Fig. 7h. The same shell as fig. 7o, seen from the inside, showing the grooves. 
Fig. 7c. Dorsal view of an individual from the seventh terrace, showing the reduced 
size of the beaks. 
2 LT 
MPCCCLXXXIX.—B. 
