VIII 
ILLUSTRATIONS. 
Barnacles oe Japan and Bering Sea: Page 
Fig. i. Scalpellum rubrum 63 
2. Scalpellum japonicum 67 
3. Scalpellum molliculum 69 
4. Heteralepas japonica 71 
5. Heteralepas vetula 72 
6. Balanus rostratus apertus 74 
7. Balanus evermanni 76 
8. Balanus hoekianus 77 
9. Balanus hoekianus 78 
10. Balanus callistoderma 79 
11. Pachylasma crinoidophilum 82 
Food value of sea mussels: 
Fig. 1. Curves showing results of metabolism experiments 104 
2. Apparatus for cleaning mussels preparatory to canning or other preservation process. 112 
Natural history of the American lobster: 
Fig. 1. Giant lobster from New Jersey 197 
2. Left second pereiopod of first larva of lobster 226 
3. Sectional view of antennal segment to show statocyst 239 
4. Locked sliding joint of big claw of lobster 255 
5. Locked sliding joint of big claw of crab 256 
6 and 7. Great first and small left third claw feet of adult lobster 258 
8. Base of right great cheliped of fourth-stage lobster from below 260 
9 and 10. Right great cheliped of fourth-stage lobster from above 261 
11. Diagram to show serial arrangement of spines in the toothed forceps of lobster 262 
12. Projection of serial teeth in segment of big claw of large adult lobster represented in 
figure 13 264 
13. Large segment of right toothed claw from above, to show periodic teeth 264 
14. Left great claw foot of first larva 266 
15 and 16. Left and right future toothed and crusher claws of lobster in eighth stage, 
seen from above 267 
17. Outline of great claw tip 268 
18. Outlineof corresponding partof big claw shown in figure 17, but in second larval stage . 268 
19. Outline of corresponding part of great claw shown in figures 17 and 18, but at third 
larval stage 269 
20. Outline of corresponding part of big claw represented in figures 17 to 19, but at fourth 
stage 269 
21 and 22. Right and left forceps of lobster 24 mm. long, reared in captivity, and ir 
months old, in eighth or ninth stage 270 
23 and 24. Serrate margins of claws shown in figures 21 and 22 271 
25. Armature of right crusher of female lobster 35 mm. long and at approximately tenth 
stage 272 
26 and 27. Profile and horizontal projection of larger division of right toothed forceps of 
male lobster immediately before molt 279 
28 and 29. Partial profile, and projection of armature of same claw shown in figures 26 
and 27 but immediately after molting 279 
30. Diagram to illustrate growth in a single generation of lobster’s eggs during a period of 
nearly 3 years, from an initial stage in ovary to time of hatching 296 
31. Diagrams of sperm shells of the lobster before, during, and after capsular explosion. . 314 
32. Diagrammatic section of sperm cell in capsular explosion 315 
33. Outlines to show relative sizes of lobsters’ eggs when laid and when ready to hatch . . 326 
34. First larva, or first swimming stage of lobster 329 
