498 WILLIAM K. GREGORY 



Starks shows that the skull and shoulder girdle of Sphyraenidae, 

 Atherinidae, and Mugilidae present a number of peculiar charac- 

 ters in common, among which are the following: (i) epiotics of 

 adult produced backward and more or less divided into bristle- 

 like filaments (2) supraoccipital developed posteriorly, not ex- 

 tending above level of balance of cranium, (3) postclavicle 

 divided into superior and inferior parts (Starks). 



The Polynemidae or Threadfishes of the shores of the tropical 

 seas, and the deep sea Chiasmodontidse present many detailed 

 resemblances 1 to the Sphyraenidas-Atherinidae-Mugilidae group, 

 and probably belong in the present order. Jordan ('96) notes 

 the resemblance of this family to the Sciaenidae of the Acanthop- 

 terygii on the one hand and to the Mugilidae of the present order 

 on the other; but remarks that in both cases the resemblances 

 may be merely analogical. 



The Crossognathidae (a Cretaceous family including Crosso- 

 gnaihus and Syllcemus of the American Cretaceous) are regarded 

 by Smith Woodward as forerunners of the Percesoces, Crosso- 

 gnathus agreeing very closely (so far as known) with the existing" 

 Atherines, but differing in having one continuous dorsal fin with 

 the right and left halves of each spine not completely fused 

 together (Smith Woodward) , — a very primitive condition. How- 

 ever, Boulenger (1904, p. 565) believes that this family should 

 probably be placed with or near the Clupeidae among the Iso- 

 spondyli. The earliest members of the families Mugilidae, Sphy- 

 raenidae, and Atherinidae occur in the Upper Cretaceous of 

 England, Colorado, and New Mexico. (Zittel, 1902). 



Superorder Acanthopteroidei (cont'd). 

 (Plate XXIX.) 

 Order Anacanthini 2 (J., Mutter) 

 The Cods. 

 The order Anacanthini, properly including only the true Cods 

 (Gadidas) and their allies (Macruridag, Muraenolepididae) was 

 formerly burdened by the inclusion of the Heterosomata 

 iBoulenger, 1904, pp. 640, 641. 



2 a, avd, privative, anavOa, thorn, spine, in allusion to the typically 

 spineless condition of the anterior dorsal fin. 



