140 DR. GIBBES' MONOGRAPH OF THE 



exception of the figures published by Dr. Morton,* and a few by Dr. Harlan,! no 

 attention has been given by American naturalists to the fossil Squalidce. In the 

 publications on Tertiary Geology, by Conrad, Vanuxem, Lea, Rogers, Hodge, &c., 

 they are merely noticed as occurring, but no attempt has been made to arrange or 

 describe them. 



In some of the early works on Fossils, we find notices of the teeth of SqualidcB 

 under the names of Bufonites and Glosso-petr(Z,X and in Sir John Hill's " History 

 OF Fossils," (London, 1748,) are some very good figures of species easily recognized 

 in our collections. His general description being condensed, I take from it the 

 following graphic and comprehensive though poetical paragraph : 



" In shape they are usually somewhat approaching triangular, and some simple, 

 others tricuspidate or having a smaller point on each side the large one ; some of them 

 are very long, others shorter, and some very broad in proportion to their length ; 

 others as remarkably slender, and narrow ; many also of them are quite straight, but 

 they are not unfrequently met with crooked, and are bent in all the different 

 directions, some inward, some outward, and some sideways, either to the right or left. 

 Many of them have their edges plain, others are serrated more or less deeply, and 

 some of them are undulated or shaped like the figure of a flaming sword at their 

 extremities, and more slightly serrated besides ; they are of as various sizes as 

 figures, the larger ones being found of between four and five inches long, and the 

 smaller of less than a quarter of an inch. They are found of vast numbers in 

 Germany, but no where so common as in the island of Malta." 



Malta seems even in our time to be the prolific source of these fossils, as M. 

 Agassiz mentions the frequency of specimens in various European collections 

 marked from this locality. 



In attempting to trace the history of fossil Squalida, I find little to refer to that 

 M. Agassiz has not given, and I am forced again to acknowledge, as Dr. Mantell 

 has emphatically done in his " Medals of Creation," as to fossil Fishes, that to his 

 great work am I indebted for a large portion of my text. 



Formerly the character of the skeleton, whether osseous or cartilaginous, and the 

 number and position of the fins, were the bases of classification of Fishes, but the 

 observation and experience of the distinguished naturalist I have named, have caused 

 him to arrange them by the form and structure of the scales. His division into orders 

 has been continued into genera, founded on his own and the microscopic researches 



* Synopsis of Organic Remains, &c. f Medical and Physical Researches. 



JScilla was the first who detected as the teeth of sharks the supposed Glosso-petra (petrified tongues of serpents). 

 Even at this day I have had them sent to me as petrified birds-tongues. 



