502 WILLIAM K. GREGORY 



pididae through Aipichihys. On the other hand., all these and 

 other deep-bodied families, such as the Bramidae, Kurtidae, 

 Carangidae, Menidse, Bathyclupeidae, Caproidae (Antigoniidae) , 

 Zeidae, Amphistiidae, Chaetodontidae, may be the result of par- 

 allel evolution from similar but distantly related Cretaceous 

 families. Some of the Acanthopterygii may have been derived 

 from Cretaceous Percesoces (compare, for example, the suggestive 

 resemblance of Scicena to Polynemus), others from Cretaceous 

 Haplomi (e. g. Berycidae, Aphredoderidae, from Percopsidae) . 

 Again the presence of Berycidae, Stromateidae, Scorpididae 

 {Aipichihys), Sparidae, in the Upper Cretaceous and the flores- 

 cence of the order in the Eocene would push back the prob- 

 able origin of the different sections of the order to the Middle 

 Cretaceous, when very many Isospondyli and Haplomi were 

 doubtless independently evolving in the direction of the Acan- 

 thopterygii At any rate all the ancestral Acanthopterygi 

 probably were short-bodied, with the typical vertebral formula 

 of 10 + 14, and all were in process of reducing the ventral 

 fin-formula to I, 5 (Boulenger). 



The Acanthopterygii very early enjoyed an adaptive radiation 

 unequalled by that of any other order of fishes, so that by Lower 

 Eocene times Scombroids, Percoids, Labroids, Plectognaths, 

 Scorpaenoids, Cottoids, Goboids, and Blennoids were already 

 well differentiated. The history of the order since the Eocene 

 is not fully known (Woodward). 1 



Superorder Acanthopteroidei (cont'd). 



Order Acanthopterygii Cuvier. 



Suborder Percomorphi Cope. 



Division Nomeiformes {divisio nova). 



There is considerable divergence of opinion as to the systematic 

 position of the group of marine fishes formerly classified by 

 Jordan under the families Nomeidae or Portuguese-men-of-war- 

 fishes, Centrolophidae or Rudder-fishes, Stromateidae or Butter- 



l Cat. Foss. Fishes, Brit. Mus., Part IV. 1901, p. xi. 



