NATURAL HISTo RY . 347 



From that clear space, where, in the cheerful ray 

 Of the warm sun, the scaly people play." CRABBE. 



Sub-order I. Holostea. 



1122. JFJiy is the first sub-order of tJie ganoidea called 



kolostea ? 



From oloSj the whole, and osteon, a bone, in reference to the 

 feet of their being covered with a suit of scales or bone. 



Sub-order II. Chondrostea. 



1123. Why is the second sub-order of ganoidea catted 



Chondrostea ? 



From chondros, a cartilage, and osteon, a bone, signifying 

 the gristly nature of the fish. 



ORDER V. SELACHIA. 



1124. Why is the fifth order of fishes catted selachia? 



From selachos, a Greek common noun, signifying a gristly, or 

 cartilaginous fish. 



The skeleton in the selachia is entirely of a cartilaginous nature. The skull 

 consists of a cartilaginous capsule, composed of a single piece without any 

 indications of suture. The structure of the jaws varies considerably. They are 

 divided into t ico sub-orders : 



Sub-order I. Holocephala. 



1125. Why is the first sub-order of selacia called holocephalaf 



From olos, whole, and cephale, head, meaning that the head ic 

 one entire piece or skull. 



1 1 26. The holoccphala are all oviparous, and their eggs, like those of the sharks 

 ar.d rays, are enclosed in a strong, horny capsule. 



Sub-order II. Plagiostomata. 



1127. Why is the second sub-order of selachia called plagiosto- 

 mata f 



From plagios, transverse or oblique, and stoma, mouth, in 

 reference to the oblique form of the mouth, which is always arched, 

 and contains numerous rows of teeth. The mouth is also wide, and 



