Stiulics on mai'ino Oslrarods 



137 



M a t u ]• e f (' in a 1 e s: 



1 specimen with a shell-length cil' 3,65 mm. 



5 specimens ,, 



4 



4 



2 



Mature m ales: 



) J >? 



J? j> 



„ 3,6 



„ 3,5 



„ 3,45 



„ 3,4 



,, 3,35 



„ 3.3 



Mean 3,46 mm 



10 specimens with a shell-lenpth of 3.3 mm. 

 •i ., ,, ,, ,, ,, ., o,.^o , 



1 specimen „ „ „ „ ., 3.2 



^ ?5 JJ )) J) J) 7? '^•A J 



Larval stages: 



Stage I: Fnrca with 8 claws (males and females). 

 4 specim(>ns with a shell-length of 2,9 mm. 

 „ .. ■ - ., :, 2.85 , 



Mean 3.27 mm. 



2 

 4 

 3 



„ 2,8 

 „ 2,7 



Mean 2.81 mm. 



Stage II: Fnrca with 7 claws. 



3 specimens witli a shell-length of 2,4 mm.j 



5 „ „ „ „ „ „ 2,3 „ I Mean 2,32 mm. 



1 specimen ., „ „ „ „ 2,2 „ I 



Stage III: P^irca with 6 claws. 



1 specimen with a shell-length of 2,0 mm.j 



5 specimens ,, ,, „ „ ,, 1,9 ,, [ Mean 1,01 mm. 



1 specimen ,, ,, ,, ,, „ 1,85 „ j 



Stage IV: Furca with 5 claws. 



1 specimen with a shell-length of 1.55 mm,} Mean 1,55 mm. 



Stage V: Furca with 4 claws. 



1 specimen with a shell-length of 1,35 mm. 



Mean 1.31 mm. 



4 specimens ,, ,, „ ,, ,, 1,3 



G r o \v t h - f a c t o r, found empirically — 1,21. 



Estimated lengths of the last five larval stages: 



2,81 : 1,21 = 2,32; 2,32 : 1,21 = 1,91; 1,91 : 1,21 ^^ 1,58; 1,58 : 1,21 1.3 

 (2,81) (2,32) (1,91) (1,55) (1,31) (actual mean.s). 



Length of Stage I, 2,81 nnn. x 1,21 = 3,4 mm. 



Zoolog. bidr.ag, Uppsnla. Siippl.-Bd. 



18 



