546 



Fishery Bulletin 94(3). 1996 



c 



4. 2 



3. 8 



■S 3.4 



3 2. G 



2. 2 



1 . 8 



/ pealei 

  I plei 



□ D 





D " 



a [ 



a 

 ■r a 



i 



>.t. 



:.j 



S ^ c D ° D 



rJ n + on 



□ 



r 



. m 



30 



90 



120 



1 50 



60 

 Mantle length (mm) 



Figure 14 



Cluster plot of gladius width/rachis width (GW/RW) on 

 mantle length (ML I for Loligo pealei and Loligo plei. 



ratio alone and this index in combination with ei- 

 ther FCL/ML, GW/ML, NCL/ML or RW/ML. The RW/ 

 ML ratio in combination with FCL/ML, GW/ML, or 

 NCL/ML provided for similar levels of accuracy. In 

 contrast, L. plei could be correctly classified at 100% 

 accuracy with the combination of FCL and RW (Table 

 8). Correct classification levels of 98% and 99% were 

 obtained when RW was combined with GW or NCL, 

 respectively. High levels of separation in L. plei also 

 occurred with the indices GW/RW or RW/ML in com- 

 bination with selected indices (Table 8). With the GW/ 

 RW index alone, 98% of the L. plei specimens were 

 correctly classified. 



Structure of the gladius 



The gladius in L. pealei is broad and feather-shaped 

 in all specimens (Fig. 17, A and B). The gladius is 

 more rounded in females than in males. The great- 

 est gladius width occurs at the mid-point of the vane. 

 The ratio of the greatest width of the gladius to the 

 greatest width of the rachis ranges from 2.26 to 3.36 

 in males and from 2.74 to 3.52 in females. The ra- 

 chis has a single median rib with marginal ribs on 

 each side that fuse in the posterior 1/3 of the rachis. 

 The anterior and posterior tips of the rachis are 

 pointed. The vane is broad and without ribs. The 



4 



20 



20 



40 



1 . 5 



/ pealei 



2. 5 



3. 5 



Gladius width/rachis width (mm) 



Figure 1 5 



Frequency histogram for gladius width/rachis width (GW/ 

 RW l for Loligo pealei and Loligo plei 



- 3 



1 * i i 



1 ' « #ii 





■'5'' \N' 



 : ' , w •' 





J 2 



*" - 



- 5 



Discriminant function 1 



Figure 16 



Discriminant analysis plot for Loligo pealei (function 1) 

 and Loligo plei I function 2). 



