28o 



Bulletin 39 



45« 



Page 



22. Neritina viridemaris Maury, Middle Creek, enlarged 159 



23. Alaba turrita Guppy, Estrella River, height 5 mm 153 



PI.ATE 16 (19) 



Fig. I. Pecten MacDonaldi, n. sp., type, Gatun (Toro limestone) 



right valve, height 96 mm 198 



2. Pecten MacDonaldi, n. sp. , cotype, same locality, left valve 



height 79 mm. 



3. Pecten gatunensis, Chagres Spillway, right valve, height 



62 mm 197 



4. Pecten gatunensis, same locality, left valve, height 48 mm. 



5. Pecten levicostatus Toula, Hill No. 2. Banana River, slight- 



ly reduced 199 



6. Pecten levicostatus Toula, same locality, left valve, slightly 



reduced 



7. Pecten levicostatus Toula, same locality, right valve slightly 



reduced 



PI.ATE 17 (20) 



Fig. I. Amusium luna Brown and Pilsbry, Chagres Spillway, some- 

 what reduced 205 



2. Pecten preglyptus, n. sp.. Codes Creek, natural size (type).. 202 



3. Amusium bocasensis, n. sp. , Bocas del Toro, natural size, 



cotype 206 



4. Amusium bocasensis, n. sp., Bocas del Toro, interior of right 



valve. 



5. Pecten coralliphila, n, sp., type, Port Limon, slightly en- 



larged 1 99 



6. Pecten coralliphila, n. sp., Port Limon, left valve 199 



7. Pecten preglyptus, n, sp., interior view of type, natural size 202 



PLATE 18 (21) 



Fig. I. Ostrea megodon Hanley, Banana River, natural size 195 



2. Glycymeris canalis Brown and Pilsbry, Comadre Creek, about 



natural size 177 



