486 WILLIAM K. GREGORY 



be separated by the normal characters of the gills and coracoid, 

 from the Acanthopteroidei by either (i) the abdominal or sub- 

 abdominal position of the ventral fins, which (save in Percopsidae) 

 are entirely separated from the pectoral arch, or (2) by the feeble 

 development of spines in the fins, or (3) in the Haplomi, Salmo- 

 percae by the open air bladder, or (4) by the high number of 

 rays (usually more than six) in the ventrals. 



The adipose dorsal fin seen in Salmonidse, Nematognathi, 

 Characinidae among Malacopteroidei is retained in some families 

 (Scopelidas, Alepidosauridae, Percopsidae) of the present super- 

 order. The number of rays in the ventral fins is progressively 

 reduced as follows: Iniomi 10 to 5, Haplomi 11 to 3, Salmopercae 

 9, Synentognathi 6, the number thus being higher, as a rule, 

 than in the Acanthopteroidei. The inarticulated rays or spines 

 in the fins exhibit various stages of development but are never 

 numerous: absent or at most incipient in Scopeloids and true 

 Haplomi, Synentognathi, distinct but very few in Salmopercae. 

 A separate spinous dorsal is never developed. The soft dorsal 

 is nearly always well back (save in Salmopercae) usually opposite 

 or nearly opposite the (usually short) anal. The parietals • are 

 usually (save in Galaxoidea) separated by the supraoccipital. 

 By this character the Mesichthyes may be separated from the 

 Heteromi, from which they are further distinguished by the 

 normal non-anguilliform body and the broadly homocercal tail. 



Our division of the superorder is as follows: 



Superorder Mesichthyes {Hay) mihi. 

 Order 1. Haplomi (Gill) Boulenger 



Superfamily Aulopoidea (Gill) (Iniomi Gill) 

 Esocoidea Starks 

 Dalloidea nom. nov. 

 Pceciloidea Starks 

 Amblyopsoidea Starks 

 Stephanoberycoidea nom. nov. 

 (Incertas Sedis ) 

 Fam. Chirothricidae (af. Iniomi?) 

 " Kneriidae 

 Superfamily Galaxoidea nom. nov. (af. Isospondyli ?) 



