26 
varying from 2} inch to 4 inches, the grades being 
numbered as follows :— 
No. 1 shelis over 4 inches diameter. 
ree over 3% inches and under 4_ inches diameter. 
” 3 ” a6 ) a2 ” 
” 4 ”) 3% ” ” oe ” 
Fy et ” 3 ” ” Bh ” 
” 6 ” 24 ” ” 3 ” 
i ei/ ” 2 AG ” ” 22 ” 
, 8 ” 24 3) ”) 2-35 b] 
‘ 9 9 24 ” ” oie ” 
The following table shows the average proportion of 
shells of the different sizes fished in an average season, 
IQIO-I1, Viz :— 
Grade. Number, Diameter. Percentage. 
I 314 Of and above 4 inches, 2 
2 1,130 ” 33 be} = 
3 35369 » 35.1 as I 
4 10,153 ” 3t or 4 
5 41,663 »» So |r 15 
6 759725 » 24 27 
7 535430 ” 2a5 of 19 
8 69,623 9 25 » 25 
9 25,918 >» 25 ” 9 
2, 91,330 
In addition to the above were :— 
22,316 undersized shells (under 2} inches diameter) 
12,952 wormed (of all sizes). 
The above gauges are adopted from the gradation of 
gauge sizes employed by the Calcutta buyers in sorting 
their shells: prior to 1910, this sorting of shells was not 
practised by the Government staff, the shells being 
divided into three lots only, (a) those above 23 inches 
diameter, (4) ‘medium ” shells, below 22 inches diameter, 
and (c) wormed shells, and sold ez 6/oc on taese figures. 
Sorting into grades before sale enables purchasers to 
assess the value of the shells with accuracy and is one of 
the improvements introduced since the conduct of the 
fishery passed into the hands of the Fisheries Depart- 
ment. 
“Wormed” shells are those tunnelled by the laby- 
rinths made by decalcifying burrowing sponges of the 
genus C/zone. The extent of infection varies greatly 
from bed to bed ; usually it is greatest on the near shore 
