548 NAOKI SUGITA 



Areaz'". Area aa. 



I I 



III. = narrow; Pyr. crowded. III. = ^ X III of area z'". 



IV. =2 X III; colls closer IV. = | X IV of area z'". 



crowded near III. V. = broad; IPyr. 



V. = 2 X (III + IV); cells dis- VI 



persed. 

 VI. = V. 



The areas appearing in my sections are collated below, with 

 the corresponding areas from Fortuyn's map. The laminar 

 structure was found generally similar to that described by 

 Fortuyn. 



Sagittal sections {fig. 2) Fortuyn's map 



Area AA'-BB' f andf 



Area BB'-CC j or n 



Area CC'-DD' w 



Area DD'-EE' not precisely described, probably o? 



Area EE'-FF' .\s'? 



Frontal sections {fig. 4) 



Area GG'-HH' c 



Area HH'-KK' f 



Area KK'-LL' f 



Area LL'-MM' j 



Area MM'-OO' k 



Area 00' h + h" 



Horizontal sections {fig. 6) 



Area PP'-QQ' c 



Area QQ'-RR' f ' 



Area RR'-SS' f 



Area SS'-TT' j 



Area TT'-UU' p 



Area UU'-VV .w 



Area VV'-WW h' 



Area WW'-XX' not precisely described, probably o? 



Area XX'-YY' " s'? 



Thus we see that the description by Fortuyn of the cortex of 

 the Norway rat is in the main applicable to the albino rat. This 

 is, of course, what we should expect. However, there appear to 

 be some slight differences shown by the areas VV'-WW, WW- 



