PRESIDENT'S ADDRESS. Ivii. 



owing to the researches of Hugh Miller, Pander, and 

 Traquair. The head and half the body are covered with bony 

 plates, forming a buckler, and a breastplate articulated at the 

 sides. The rest of the body is covered with ganoid scales. 



Coccosteidae. Coccosteus has its maximum development in the 

 Old Red Sandstone. The helmet and cuirass are firmly united ; 

 there is no trace of pectoral fins, which characterise Pterichthys. 

 The unprotected part of the body shows an ossification of the 

 neural and haemal spines ; both jaws are furnished with from ten 

 to twelve teeth on each side, anchylosed to the bone. The 

 blank spaces between the neural- and haemal-spines indicate the 

 position of the perished notochord. 



Lepidosteidae. Head and trunk much elongated, the large 

 teeth are set on the margin of the jaw, the rest are com- 

 paratively small. The genus Lepidosteus made its first appearance 

 in the Tertiary Age. It now only lives in the rivers of North 

 and Central America and Cuba. Fossil remains of it have been 

 found in Europe and in North America. 



Lepidotidse, Lepidotus.The fulcra of the fins are well devel- 

 oped ; the genus occupies an important place in the Mesozoic 

 rocks, from the Trias to the Cretaceous and is largely represented 

 in the intermediate Jurassic, both in Europe and Asia. L. minor 

 is ve.ry common in the Purbeck Beds in the neighbourhood of 

 Swanage, L. maximus is abundant in the Kimmeridgian of 

 Bavaria ; a few of its teeth have been found in the Kimmeridge 

 Clay of Kimmeridge. 



Ccelacanthidae. With this family we come upon a group of 

 fishes, not found in the older Palaeozoics, but extending from 

 the Carboniferous to the Upper Cretaceous, and linking the 

 extinct Osteolepis of the Old Red Sandstone with Calamoichthys, 

 a native of tropical Africa, which has not yet been found in a 

 fossil state. Polypterus, another genus of the same family and 

 which lives in the waters of the Upper Nile, is closely allied to 

 the extinct Osteolepis. 



Accipenseridae. Sturgeons are geologically one of the most 

 recent of the family of the Ganoids. The two living genera 



