Bullae are rounded or irregularly shaped blisters containing serous or seropurulent fluid.They differ from vesicles only in size, being larger than 1 cm.
Its compositional ichthyofauna differs from its consecuting fiver systems,and has momentous significance on succession of fishes and ichthyofauna dividatur in watershed of North China.
This character differs from other Ordovician source rocks elsewhere in the world such as Kukersite Kerogen in Estonia and Guttenburgen type source rocks in USA.
Warp knitting differs from weft or filling knitting in that the loops are formed in a vertical or warpwise direction and yarns lying side by side are interloped.
The adjacent structures of the ostia differ from each other by the different location of the ostium.The clinical significance of the ostium and the nasofrontal duct were discussed.