NATURAL HISTo RY . 347 



From that clear space, where, in the cheerful ray 

 Of the warm sun, the scaly people play.&quot; CRABBE. 



Sub-order I. Holostea. 



1122. }Hiy is the first sub-order of tlie ganoidea called 

 kolostea f 



From olos, 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 called 

 uhondrostea ? 



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 called 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. Thev are 

 divided into two sub-orders : 



Sub-order I. Holocephala. 



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

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



one entire piece or skull. 



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

 and rays, are enclosed in a strong, horny capsule. 



Sub-order II. Plagiostomata, 



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

 mata ? 



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

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

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



