Bull. U S. F. C. 1895. The Amercan Lobster. (To face page 89.) 



Plate C. 



Cut 8. -The gastrolith of a lobster nearly ready to raolt, removed from the wall of the 

 stomach. 



a, seen from the outside; 6, from the inside (toward cavity of stomach), and c, in 

 transverse section. From adult rnale, lobster Xo. 2, table 24. For chemical analysis 

 of this gastrolith, see Appendix II, ~So. 4a of table. Natural size. 



X)G 



Cut 10. — Section of the deciduous portion of old cuticular 

 lining- of stomach overlying gastrolith. See cut 9, oc'. 

 89 diameters. 



,SIC 



^^mMSMii^^ 



Cut 11. — Section of gastrolithic sac from wall of stomach 

 underlying gastrolith, as it appears while the latter is 

 still in place in the stomach. From a lobster nearly 

 ready to molt. August 2, 1894. See cut 9, gp. 89 diam- 

 eters. 



D, connective tissue of dermis, ep, chitinogenous 

 epithelium, no 1 , new cuticle. 



Cut 9. — Diagrammatic section through the wall of the 

 stomach of a molting lobster, cutting gastrolith. 



ep, chitinogenous epithelium, gg, gastrolith, a differ- 

 entiated part of the old cuticle, gp, gastrolithic sac. n. 

 c 1 , new cuticle of gastrolithic sac. iw, outer side of 

 stomach-wall next body -cavity. New 0, new cuticle. 

 oc 1 , the deciduous part of cuticle overlying gastrolith. 

 Old 0, old cuticle. S, interior of stomach. WS, wall 

 of stomach. 



Drawn by F. H. Herrick. 



