240 



DR. W. jST. F. woodland ON THE 



Text-fig. 61 (x circ. 1000). 



Microphotograph of transverse section across thin region of gns gland of Ferca (fixed 

 with Zenker's Fluid), showing foam-like mass of bubbles (F.B.) on surface 

 {cf. PI. IX. fig. 70). 



Text-fig. 62 (X circ. 1000). 



■*m-^ 



Microphotograph of transverse section across thick region of gas gland of Perca (fixed 

 with Absolute and Glacial Acetic), showing extruded gas bubbles (B) on surface 

 [cf. PI. IX. fig. 71). The " spent " condition of the cells is also shown. 



