L. W. BVRNK 



117 



(W) OfMi,. fonnula " " , , 21 or 8-4. 7 



III III. + k '" 



3. Ainoug the 79 asyininctric;il in both serics tlie lollowiiig anaiiyeiiicnts 

 occur: — 



(i) W'Iu'io botli .series have more plates on the same sidc, 40 (ir 10 '7^,. 

 (a) Of the tbrmula rA — , 18 or 7'2 "/ . 



(b) Of the fonnula " j " "*" f , 22 or 8-8 7„. 

 ^ ' m m + l '° 



(ii) Whore the phites of one siile jin'jioiMli'rate in one seriös anil of the 

 otlier in the other. 



(«) Where the total number of phites on the right side o(iiials the total 

 nuniber on the left and the specimen attains a " secondary symmetr}'," 32 or 



12-8 7.. 



)( + k n 



(1) Of the fornuila 



111 III + 



7;. 13 or 5-2 7, 



(2) ( )f the formula 



11 I n + k 

 in + k I 111 



1!) or 7-0 7„. 



