No. 435.] SHELL OF UTTORINA LI TORE A. 



clear or it may show a yellowish stain or fine lines of growth 

 parallel to the surface of the lumen. The secondary shell has 

 evidently been deposited after the formation of the primary shell, 

 and there is a considerable amount of it, even in this very young 

 specimen. In the upper part of the spire the secondary has 

 nearly filled the original cavity of the primary shell, so that open- 

 ings 2 and 3 are almost obliterated, and No. 1 is quite so. 

 Moreover the lumen at openings 2 to 4 is eccentric, the thick- 

 est part of the secondary shell being on the outer side. It will 

 be noticed, also, that the'outlines of the primary lumen at open- 



outer wall of the first whoi 

 secreted, there would be ai 



Fig. 2 represents a simih 

 large as Fig. 1, that is, 5 b 

 condition with well marked 

 with an acute apex, but the 



Assuming that Fig. 2, hi 



that the 



the section. In the first plac 

 numbered 5 to 9 agree in t 

 the correspondingly numberei 



