Plate XIII. 



W 7 



ORGANISMS CONSTITUTING FOOD OF MATAGORDA BAY OYSTERS. 



1-6. Navicula elliptica, 660. \ it.-i- 7. Pleurosigma intermedium, 100. i Vi'ut 



Schmidt). Smitl 



1 Pleurosigma fasciola, 100. (After 9-11. Navicula didyma, 660 \m - 

 Smith. 



