360 
great ‘probability that the shell-covered forms of all kinds which 
have the protoconch—namely, the ancient and modern Gastro- 
poda, Tentaculites, and the ancient Pteropoda, and all the radical 
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Fig. 7. 
Fig. 3.—Aspect of the apex of the conch in Orth, unguis Phill., after the protoconch has 
been shed in the usual manner. 0, conch or shell of the apex; ec, cicatrix. 
Fig. 4.—Aspect of the apex, after the protoconch has been accidentally broken off, frac- 
turing the outer shell, and exposing the cicatrix. 6c, as before. 
Figs. 5-7.—Apex and protoconch of Orth. elegans Munst. from the front, side and above. 
a, protoconch ; 0, shell of apex. 
Figs. 8, 9.—Anotherindividual, said to be of the same species, less magnified. ab, as 
before. The author has also, in Spy. crotalwm, traced the strice of the outer shell on 
the protoconch itself, showing the continuity of the shell over this part (a), and 
completing the evidence that it must have been the shell which enclosed the em- 
bryo, and could not have been a mere plug, as asserted by Barrande (Syst. sil., 
pl. 488). (See Figs. 10 and 11, p. 361), 
