297 
Littorina parva 
1 . 
Shell 9 m. m. 
Bad ula 21 
m. m. 
2. 
— 12 
— 25 
- 
3. 
— 13 - 
— 27 
- 
4. 
— 14 - 
— 35 
- 
5. 
— 14,5 - 
— 29 
- 
6. 
— 14,5 - 
— 30 
- 
7. 
— 16 - 
— 37 
- 
8. 
— 17 - 
— 37 
- 
9. 
— 17,5 - 
— 34 
- 
10. 
— 18 - 
— 42 
- 
Littorina littorea 
• 
1 . 
Shell 14 in. m. 
Kudula 28 
m. m. 
2. 
— 16,5 - 
— 34 
- 
3. 
— 17 - 
— 31 
- 
4. 
— 20 - 
— 42 
- 
5. 
— 20 - 
— 46 
- 
6. 
— 23 - 
— 47 
- 
7. 
— 25 - 
— 48 
- 
8. 
— 28 - 
— 54 
- 
9. 
— 28,5 - 
— 64 
- 
10. 
— 33 - 
— 56 
From these and Teilman-Friis’s figures et may be concluded that 
small dwarfed forms have on an average a proportionally longer 
radula than the well developed specimens, but no constant charac- 
teristic separating the two forms can be deduced from the relative 
ength of the radula. 
The number of denticles in the lateral teeth of Littorina litto- 
rea greatly differs in the figures of Lovén (6), Woodward (13), and 
G. O. Sars (20), but it must not be concluded from this that any 
great variation takes place. None of these au thors has treated the 
leetli separately, but without doing so it is almost impossible to 
