1014 CLASS PISCES. 



Perca and Labrax ; and also Plioparchus, which does not appear 

 allied to any existing genus. 



Family Pristipomatid^e. — This family includes the existing 

 Pristipoma, which Dr Giinther refers to the Peradce. It occurs 

 fossil in the Eocene of Monte Bolca ; and Dr von Zittel would 

 place Sci&nurus, of the London Clay, in the same family. 



Families Aphrodedirid^e and Asineopid^e. — These two families 

 are proposed by Professor Cope for the reception of certain North 

 American Eocene Fishes more or less closely allied to the Percoids. 



The first family includes 

 the genus Aphrodedirus, 

 Erismatopterus, and 

 Amphiplaga, and the 

 second Asineops. Pro- 

 fessor Cope suggests 

 that Pygceus, from the 

 Middle Eocene of 

 Monte Bolca, should 

 perhaps be included in 



Fig. 948. — Skeleton of Smerdis minuta ; from the Upper " Jr ' 



Eocene of Aix, Provence. SUBORDER 5. LOPHO- 



branchii. — In this 

 small, and to the palaeontologist unimportant, suborder the gills 

 are reduced to small round lobes ; the gill-cover has only one large 

 plate ; and there is a dermal bony skeleton taking the place of the 

 soft integuments. The swim-bladder has no duct. 



Family Solenostomatid^e. — The skull is produced into a long 

 rostrum, terminated by the toothless mouth. The gill-openings are 

 wide ; there are two dorsal fins ; and all the others are well developed. 

 The only existing genus is Solenostoma, allied to which is Soleno- 

 rhynchus, of the Italian Eocene. 



Family Syngnathid^e. — The Sea-horses and Pipe-fishes differ 

 from the preceding family by the small gill-opening, the single 

 dorsal fin, and the absence of the pelvic fins. The first section, 

 in which the tail is not prehensile, includes the Pipe-fishes, and is 

 represented in the Miocene of Italy and the Middle Eocene of 

 Monte Bolca by the existing genera Syngnathus and Siphonostoma, 

 and also by the extinct Calamostoma, which is allied to Hippo- 

 campus, but has a caudal fin. The Sea-horses do not appear to be 

 represented in a fossil state. 



Suborder 6. Plectognathi. — The last suborder is likewise of 

 small extent, and is characterised as follows. The skin may be 

 naked, or covered with rough scales, scutes, or spines, and the 

 skeleton is imperfectly ossified. There is a small opening leading 

 to the pectinate gills in advance of the pectoral fin ; the bones of 



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