48 
Fishery Bulletin 1 15(1) 
Figure 5 
(A) Image of the primary ossicles of the gastric mill seen in the exuvia of a red king crab 
{Paralithodes carntschaticus) collected in Bristol Bay, Alaska, in June 2013. Included are the 
lateral teeth of the zygocardiac ossicle (z) and the medial tooth (mt) and urocardiac (u) of the 
dorsal (uro- and mesocardiac) ossicle, showing that the portion of the ossicle containing the 
arch of the mesocardiac (m, indicated by the box and illustrated in Fig. 2) was absent. (B) Im- 
age of the dorsal ossicle of the same red king crab 1 week after ecdysis, showing that the entire 
mesocardiac was present (boxed). (C) The base of the dorsal ossicle for the exuvia of a southern 
Tanner crab {Chionoecetes bairdi) collected in Marmot Bay, Alaska, in June 2014, showing that 
the urocardiac was present but the mesocardiac (boxed) and pterocardiac ossicles were absent. 
(D) Image of the gastric mill ossicles, showing that the mesocardiac (boxed) and pterocardiac 
ossicles (p) were present in the ossicle of the southern Tanner crab 1 week after ecdysis. 
elapsed time after marking (Kilada et al., 2012; Le- 
land et al., 2015). Further, determining band counts 
for crustaceans for ^vhich ages are known (e.g., ani- 
mals reared in captivity) will be necessary to further 
understand dynamics of band formation (Leland et 
al., 2015). 
Acknowledgments 
This project was funded by the Alaska Department 
of Fish and Game. Thanks are extended to C. Siddon 
and D. Pengilly of the Alaska Department of Fish and 
Game for their support and to D. Oxman for an earlier 
review of this manuscript. Three anonymous reviewers 
contributed to significant improvement of the manu- 
script through review of a previous draft. This short 
contribution is professional publication number PP-280 
of the Alaska Department of Fish and Game. 
Literature cited 
Abele, D., T. Brey, and E. Philipp. 
2009. Bivalve models of aging and the determination of 
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Beamish, R. J., and G. A. McFarlane. 
1983. The forgotten requirement for age validation in 
fisheries biology. Trans. Am. Fish. Soc. 112:735-743. 
Brosing, A. 
2014. Foregut structures of freshly moutled exuviae 
from Maja crispate, Cancer pagurus and Pseudosesarma 
moeschi (Decapoda: Brachyura). J. Nat. Hist. 48:543- 
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