118 



Bony riates of John Dory 



(b) Whcro tho pliitos »f ono side or the other prepoudcrato thcre arc 7 

 or 2"8% of the following furmula; and airangeinents : — 



The following are the particular combinations which occiir in moic thaii 5 per 

 Cent, of the 250 specimens : — 



8 I 8 



9 I 9 



in 2-5 specimens or 10 per Cent of the total. 



The niimber of the plates. 



Dr Günther in the first edition of the British Museum Catalogue gives the 



total number of plates in Z. faher as 98, or 7 occa.sionally 10 in each dorsal scrie.s 



and 9 in each anal. In the specimens under consideration the maxinia and 



minima observed were : — 



Dorsal L. Max. 10 Min. 7 R. Max. 11 Min. 7 



Anal „ „ 12 „ 7 „ „ 11 „ 7 



, ,. ... , lU-7 I 7 - 11 



and the Variation niay be diagraminaticaliy expressed z-^ — - . _ — ry . 



, r , «, ^ «432 I 8-464 , , 



The average number of plates was 34'6, s Sin ' 'argest in any 



.,..,, ,^ . 10 I 11 ,9 



iiiiiiviniial 40, in two in.stances, -— r and 



j^JJ,andtheMnallest29,;|^. 



The accompanying table and diagram show the number of plates occurring 

 in the in<lividuals of each forniula, and the nearly regulär grouping of them in 

 each instance round a inaximum of 34 or 35 ; (it must be bome in iniiid that in a 

 specimen primarily or secondarily symmetrical there must be au even number of 

 plates and that in a specimen asymmetrical in onc series an even number is very 

 uncommon). 



