402 



The Squamipinnes 



altissimus, with a very high dorsal, is fossil in the Eocene of 

 Monte Bolca. 



The Butterfly-fishes: Chsetodontidae. The central family of 

 Squamipinnes is that of the butterfly-fishes or Ch&todontida. 

 In this group the teeth are distinctly brush-like, the mouth 

 small, the dorsal fin continuous and closely scaly, and the ven- 

 tral fins with one spine and five rays. The species are mostly 

 of small size and brilliant and varied coloration, yellow and 

 black being the leading colors. They vary considerably with 

 age, the young having the posterior free edges of the bones of 



FIG. 338. Butterfly-fish, Chastodon capistratus Linnaeus. Jamaica. 



the head produced, forming a sort of collar. These forms have 

 received the name of Tholichthys, but that supposed genus 

 is merely the young of Ch&todon. The species of Ch&todontidce 

 abound in rock pools and about coral reefs in clear water. They 

 are among the most characteristic forms of these waters and 

 their excessive quickness of movement compensates for their 

 conspicuous coloration. In these confined localities they have, 

 however, few enemies. The broad bodies and spinous fins make 

 them rather difficult for a large fish to swallow. They feed 



