172 J. AWAPARA 
(a) (b) G 

Fig. 4. Marine gastropods. (a) Moon shell ( Polinices duplicatus) ; (b) Left handed whelk (Busycon 
perversum); (c) Oyster drill (Thais haemostoma); (d) Slipper shell (Crepidula fornicata). G = 
Glycine, T = Taurine, A = Alanine. 
(a) 
; G (b) G 
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T 
, 
(c) . (d) 
v4: 
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cd 
Fig. 5. Pelecypods. (a) Incongruous ark (Arca incongrua); (b) Oyster (Crassostrea virginica) ; 
(c) Bloody ark (Arca campechiensis); (d) Ponderous ark (Noetia ponderosa). G = Glycine, 
T = Taurine, A Alanine. 
