THE TURTLES 2443 



carried away, till the animal becomes exhausted, and is secured." In China and 

 Mozambique turtles are captured by means of sucking fishes, which are taken to a 

 spot where the reptiles are basking upon the surface of the water. Each fish has 

 a ring round its body to which a line is attached, and as soon as it securely fastens 

 itself by its sucking disc to the back of a turtle, both captor and captured are drawn 

 ashore. Although those of the loggerhead have a somewhat musky taste, the eggs 

 of the other species of turtle are much esteemed as articles of food, while all yield 

 a valuable oil. 



As already said, tortoise shell is a product of the hawksbill turtle, 

 and it is too often taken from the back of the living animal by the aid 

 of heat, after which painful operation the unfortunate turtle is returned to its native 

 element. As the raw tortoise shell is very unlike the finished article, with which 

 all are familiar, Bell's brief account of the process of manufacture may be quoted. 

 The horny shields, as removed from the turtle, being highly curved, " the uneven 

 curvature is first of all to be removed, and the plate rendered perfectly flat. This 

 is effected by immersing it in hot water, and then allowing it to cool under heavy 

 pressure between smooth blocks of wood, or metallic plates. The surface is then 

 rendered smooth, and the thickness equal, by scraping and filing away the rough 

 and prominent parts. In this way each plate receives an equal and smooth surface. 

 But it is in many cases desirable to employ larger pieces than can be obtained 

 from single plates, and two pieces are then united in the following manner: The 

 edges are beveled off to the space of two or three lines, and the margins, when 

 placed together, overlap each other to that extent. They are then pressed together 

 by a metallic press, and the whole is submitted to the action of boiling water; and 

 by this means the two pieces are so admirably soldered together as to leave no indi- 

 cation of the line of union. By the application of heat, also, the tortoise shell may 

 be made to receive any impression by being pressed between metallic molds." 

 Necklaces, etc.. are made by pressing the fragments and dust in molds. 



Turtles, more or less closely allied to the existing kinds, abound in 



marine strata of the Tertiary and Cretaceous epochs, some belonging 

 Turtles 



to extinct and others to the living genera. Among the latter, the gi- 

 gantic Hoffmann's turtle (Chelone hoffmanni) from the chalk of Holland appears 

 to have been allied to the hawksbill, but had a shell of some five feet in length. 

 Extinct loggerheads occur in the London Clay; and an allied extinct genus (Ly- 

 ioloma), common to the same formation and the upper Cretaceous deposits, was re- 

 markable for the great length of the bony union between the two branches of the 

 lower jaw, and also for the circumstance that the aperture of the internal nostrils 

 was placed right at the hinder extremity of the palate as in crocodiles. In strata 

 older than the Chalk, such as the Purbeck and other Oolitic rocks, we meet with 

 turtles having heart-shaped shells, but clawed limbs, and a vacuity in the centre of 

 the plastron, these forming an extinct family {Acichelyidce} from which the modern 

 turtles have probably originated. 



