310 



PRACTICAL ZOOLOGY 



TURTLES 



Turtles are favorable reptiles for laboratory study because 

 of their size, because they are easily obtained, and because they 

 are not so generally abhorred as are most other species. The 



FIG. 1 88. Skeleton of a turtle, ventral aspect; plastron removed to one 



side. 



c, costal plates; co, coracoid; e, entoplastron ; ep, epiplastron; f, fibula; 

 fe, femur ; h, humerus ; hpp, hypoplastron ; hyp, hyoplastron ; jl, ilium ; 

 js, ischium ; m, marginals ; nu, nuchal ; pb, pubis ; psc, pre^oraj oid ; py, 

 suprapygal; r, radius; sc, scapula; t, tibia; u, ulna; xp, xiphiplastron. 

 (From Zittel.) 



most striking thing about a turtle is its protective shell (Fig. 188). 

 In most species this covers almost the entire body, and the 

 legs, head, and tail can be drawn into it. Such an animal does 

 not need to run away at the approach of an enemy, and the turtle 



