THE STUDY OF ORGANS. 



with earthy matter, forming a shell (as in the lobster) : 

 it is less easily destroyed by chemical action. Fur, 



Fig. 9. — Rudimentary ears or otocysts, C, in the tail of a crustacean, Mysis, 

 the Opossum Shrimp. See next page. 



finger-nails, and feathers, are all modified appendages 



