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THE AMERICAN NATURALIST [Vol. XLIV 



tegumental glands, assuming that these have been cor- 

 rectly identified in the body in question, might lend 

 some support to this idea, for the tubercles are formed 

 by fusion of the sharp teeth, near the apex of each of 

 which a tegumental gland is seen to open, up to the 

 fourth and to even later stages of development before 

 the adult types of claw have been differentiated. I 



am inclined, however, to regard the body as the result 

 of regeneration, due to injury, in the way suggested 

 above. 



Seduced to the simplest expression, the ingrowth and 

 shell proper bore the relations shown in Fig. 5, where 

 the axis of invagination is marked by the arrow. The 

 ingrowth involves in succession the soft skin (dermis 

 and chitin-secretin epithelium), the calcified non-pig- 

 mented and pigmented strata, and the thin outer enamel 

 layer of the hard shell, but the superficial area of in- 



