and Polyides rotundus. 89 



measure of these outermost epidermal cells, taken with a screw 

 micrometer, is the following : — 



Breadth in 

 3 together = 0-01 16'" Paris. 



3 

 6 

 3 

 3 

 3 

 3 



24 



= 0-0101 

 = 00174 

 = 00112 

 =0-0113 

 =0-0125 

 = 00115 



= 00853 



Length in 

 1=0-0129'" Par. 

 1=0-0083 

 1 = 00132 

 1^:0-0085 

 1 = 00087 

 1=00103 

 1=0-0115 

 1 = 0-0121 

 1=0-0109 

 1=0-0134 

 1=0-0100 

 1=00117 

 1=00128 

 1=0-0135 

 1=0-0123 

 1=0-0140 

 1=0-0129 

 1=0-0111 

 1=0-0109 

 1=0-0117 



20=0-2307 



Giving an average for the length of 0-0115'" Par., and for the 

 breadth or width 0-0035'" Par. These outer epidermal cells show, 

 although not always, a tendency to place themselves in radiating 

 rows. 



The inner part b, fig. 1 & 2, of the stratum A, is essentially 

 formed exactly like the outer part ; the cells are only far longer 

 and broader than those of the outer part, the absolute measure 

 of the length in eight being the following : 0-0195'" ; 0-0184'" ; 

 00181'"; 00502'"; 0-0238'"; 0-0176'"; 00402'" ; 0-0563"' Par. ; 

 all eight together =0-2431"', giving an average for the length of 

 0-0303'^' Par. They are less covered with brown grains on the 

 walls, and show in the transverse section forms approaching the 

 globular, elliptical, oval, or often the rhomboidal. The relative 

 proportion of their breadth : length = 1 : 1^ to 3 or 4. I am not 

 inclined to speak of b, the inner part of the epidermal cells A, as 

 a peculiar stratum, for two reasons : first, because the transition- 

 forms between the outer part a of stratum A, and b the inner 

 part, are so gradual that no decisive difi^erence between a and h 

 could be found out, the common property being always the brown 

 or brownish grains attached to the walls ; and secondly, because 



Ann. ^ Mag. N. Hid. Ser. 2. Vol. vi. . 7 



