GREGORY: FISH SKULLS 



387 



ward or forward, like an arm. Among existing pediculates the least specialized stage of the 

 pectoral fins occurs in the toad-fishes (Batrachoidea). In Batrachoides didactylus, according 

 to Regan (1912/, p. 279, Fig. 1), the broad pectoral fin is supported by four elongate ptery- 

 gia! bones, of which the lowermost is large and distally broadened; the uppermost is some- 

 what broadened distally, the others are slender. This construction, which is not yet com- 

 pletely pediculate, would appear to be well adapted for the mode of life of toad-fishes, 

 which hide among rocks in shallow water. In the complete pediculate stage of Lophius 

 the pterygials are reduced to two long rods, the lower one resembling a flattened ulna. 

 Lophius, which is the giant of the order, has a broad flattened body for resting on sandy 

 bottoms and huge jaws and throat. The sea-mice, or Antennariidae, retain three pectoral 

 pterygials; the pectoral extremities acquire amazing facility as the fish crawls among the 

 sargassum weed. The benthonic sea-bats, Ogcocephalidae, have more or less flattened and 

 rounded bodies; their pectoral fins somewhat resemble the hind paddles of frogs or of seals 

 and are doubtless able to propel the body forward by rapid strokes of their obliquely-placed 

 surfaces. In the bag-like ceratioids the pectoral fins, while close to those of the anten- 

 nariids in ground-plan, are more or less reduced and finally almost vestigial, while the pelvic 

 fins are absent. 



The question then is, which type of body and fins among the living forms may be 

 considered to be nearer the starting-point for the group .'' The bat-fishes and all the cera- 



Branchionichthys unipinnis 



Fig. 264. " ChirorucUs" {Branchionithtkys) unipennis. After Cuvier. 



tioids may be at once eliminated, on account of their obviously extreme and diverse spe- 

 cializations. Lophius is specialized in its great size, in certain skull characters and in the 

 reduction of the pectoral pterygials to two. Even Chirolopkius naresii (Giinther, 1880, 

 PI. XXV), in which the "illicium" or fishing-rod is still obviously only the first ray of the 

 spinous dorsal fin, is relatively specialized in the huge size and extreme depression of the 

 head. As to the antennariids, many also appear to be highly specialized in external appear- 

 ance but, as will presently be shown, the South Australian antennariid Brachionichthys is 

 much less specialized and in fact seems to give several clues to the origin of the entire order. 

 In 1817 Georges Cuvier, in a remarkable memoir entitled "Sur le Genre Chironectes 

 Cuv. {Antennarius Commers.)," noted that the "fishing-rod" of Lophius was merely the 



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