220 



AVERS AND JACKSON. 



[Vol. XVII. 



3 10 



"^10 



12 : — 1 

 1 



li 

 io» 



10 

 10' 



11 



10' 



10. 

 10 



2 11 



^ 10 



11 



10 



L I 9 

 ) 1 9' 



i_a 



"9 ' 



1_1 

 9'' 



10. 

 10- 



10 

 10' 



1_0 

 "9 ' 



1 111 



^ 10 1 



1 i# 



11 



10- 



I 1-0 

 I 10' 



in 



10 



10 

 10' 



Branchial formula, 12-11: — 3 V" I ¥' ^ ¥ I To' 



1 10111 910110 o 11 1 10 3 .11 1 11 Total 1 7 

 -*■ it rg"' ^ To" I "9"' *" lolio' "^ lolio- j-ulch, 1/. 



Branchial formula, 12- 



1 fi 1 I 1_0 4 IJl I 10. \ IJL 

 -••" ""9" I T' ^ 9 I 1 0' -^ 9 



OQ 1 I 1 3 10. I 11 4 11 

 ^^ T'O I TO"' ^ 10 I 10' ^ 10 



9 11110 2 ii|i-0- 13 11114. 2 



-^ "9' I T'O' ^ 10 I 9' -^"^ 10 I 10' '^ 



1 i_2. 1 1_2 . Total, Z^. 



Branchial formula, 12-13: — 1 ^- 



Branchial formula, 13-12 : — 1 -U. | 



Branchial formula, 13-13: — 1 -9- 

 Total, 3. 



The following table is a summary of all the variations found 

 in the 162 specimens observed. 



10. 



10- 



Total number 



162 



