42 FOSSIL FISHES. 



The Notopleridce. — Well-preserved remains of the genus 

 Notopterus occur also in the Miocene Tertiary beds of Padang, 

 Sumatra. 



The Hoplopleuridce are a family of extinct fishes devoid of true 

 scales, bat having the back and sides partially protected by 

 symmetrical scutes arranged in series, and in some species by inter- 

 mediate smaller ones. 



Plinth ophor us and Dercetis occur in the Chalk of England ; and 

 Dercetis, Leptotrachelus, and JEurypholis, are abundant in the 

 Chalk of the Lebanon, from which locality a line series in almost 

 perfect preservation may be seen in the Cases. The genera 

 Pelargorhynchus and Ischyrocephalus are from the Cretaceous of 

 Westphalia, and Saurorhamphus from the Chalk of Comen, Istria. 



The Murwnidce (the "Eels" and "Conger Eels ") are spread 

 over almost all freshwaters and seas of the temperate and tropical 

 zones ; some even descend to the greatest depths of the ocean. 



They are represented in the London Clay at Sheppey ; by the 

 genus Rhyncliorhinus ; by Anguilla, Sphagebranchus, and Ophichthys 

 (Ophisurus), in the Eocene of Monte Bolca and of Aix ; aud in the 

 Miocene freshwater deposits of (Eningen. 



The Lophobkanchii have the gills arranged as small rounded 

 lobes, or tufts, attached to the branchial arches ; the gill-cover is 

 reduced to a large single plate. To this division belong the Pipe- 

 fishes, and the Hippocampus (" sea-horses "). 



The Solenostomidce are known by a single living genus, Solenos- 

 toma, preceded in Tertiary times by Solenorhynchus from Monte 

 Postale. 



The Syngnatlddce — " Pipe-fishes " — fossil species of Siphonostoma 

 and Syngnatkus, also remains of an extinct genus, Calamostoma, 

 allied to the living Hippocampus, have been found in the Eocene 

 strata of Monte Bolca, and in the Miocene of Licata in Sicily. 



Plectognathi. — In this division the skeleton is incompletely 

 ossified ; the gills are pectinate, the gill-opening narrow, the mouth 

 small ; the bones of the upper jaw are generally firmly united. The 

 ventral fins are absent or reduced to spines. 



The Scleroderma are tropical and sub-tropical fishes living on 

 Corals and Molluscs, on which they are enabled to feed by means of 

 their chisel-like teeth ; with these they break pieces off the former 

 and bore holes in the shells of the latter. 



Ostracion is found in the Eocene of Monte Bolca, and the dark 

 slates of the Canton Grlaris with the extinct genera Acanthoderma 

 aud Acanlhopleurus. Glyptocephalus occurs in the London Clay of 

 Sheppey. 



The Gymnodontes, or " Globe-fishes," are represented by the 

 genus Orthagoriscus from the English Chalk ; by Diodon at Monte 

 Bolca near Verona, at Licata in Sicily, and in the Infusorial Earth 

 at Oran in Algeria ; a distinct genus, Enneodon, occurs at Monte 

 Postale. 



