Bull. U. S. B. F., 1909. 
Plate XLII. 
Fig. 1. 
Fig. 2. 
II 
I 
Fig. 3. 
\V 
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/\^/vPWV 
L 
■ 
Sp 
13 23 
14342434 
154 3 4 2 4 345 
143 243 
I JT JIT 
Fig. 4. 
L 
1 
\ 
/V./vTVv 
: ? Wv/Vv 
[ •' V \/V\\4. V v: 
[\wvva 
1 
1 
j 
Sp 
1 3 2 34 
14 3 4 2 4 3 45 
1 5 4 3 4 2 545 345 
1434524 3 
i n nr 
Fig. 5. 
Fig. i. — Right toothed forceps of lobster in seventh -stage, seen from above, and drawn from molted shell. Dental armature of jaw, 
marked a, shown greatly enlarged in figure 3. 
Fig. 2. — Teeth from dactyl of lobster in fifth stage, showing multiple or bifurcate ducts of tegumental glands. 
Fig. 3. — Serrate margin of jaw in area marked a, figure 1, embracing series i-ii, and showing spines pierced by the ducts of tegu- 
mental glands. Cuticle only represented; enlarged about 170 times. Figures 1-3, from glycerine preparations and represented 
in optical section. 
Figs. 4 and 5. — Armature of index or propodus of right toothed forceps of lobster in seventh stage, and after molting to the 
eighth, as seen from under side, showing changes in spines of each period introduced at this molt. L, lock spine, and Sp, spur. 
