Rccherches sur les Poissons Fossiles, S35 



which they occupy on the body. By degrees they become 

 round or oval, or more or less angular, having their centre 

 of increase^) in the middle, and then all the leaflets are 

 placed one upon another, and equally bordered in every 

 side( 2 ) ; they may again possess this same form, but the 

 centre of growth approaching more or less to one or other 

 border, the concentric lines are then removed more 

 to one than to the other side, being closest on the side 

 at which the centre of increase is placed ;( 3 ) occasionally 

 the contour presents sinuosities, the lobes of which 

 being more or less large, and conspicuously marked, when 

 the leaflets of growth present these forms, and they are 

 superimposed exactly one over another according to their 

 size; ( 4 ) it is particularly on the anterior border of the scales 

 that we observed these large undulations. When these 

 lobes are acute in the form of denticulations, or very sharp 

 serratures, and which are only found on the last leaflet (the 

 preceding leaflets presenting a successive disparity in blunt- 

 ness,) it follows that such scales will have their border 

 simply serrated ;C 5 ) but whenever it is found on the border 

 of many leaflets consecutively, the border of the scale and 

 all the visible external surface of the same presents nume- 

 rous ranges of bristling prickles/ 6 ) they are then very rough 

 to the touch. It is the same when the borders of the leaves 



U) I thus name the part of the scale where the first lamina is 

 secreted in the alveolus. I call it also the centre of radiation, when 

 encircled by the delineations which ornament the surface of the scale. 



(2) Voyez dans mon selecta genera et spec. Piscium Brasiliensium, 

 Tab. D., les ecailles du Rhaphiodon gibbus, and Tab. E. those of Cory- 

 phcena immaculata. 



(3) Voyez selecta genera Tab. E. Cynebium maculatum et Caraux 

 lepturus. 



(4) Myletes bideus ; Saurus longirostris, intermedius and tmncatus. 



(5) Selecta genera, Tab. D. Rhombus ocellatus, et soleaeformis : Tab. F. 

 Corniger spinosus. 



< 6 ) Selecta genera, Tab. D. Plogusia brasiliensis. 



