ACTINOPTERI. 169 



simple or spinous, and all fin rays often articulate. Pectorals 

 placed above plane of abdomen, actinosts always present. Ven- 

 trals mostly anterior, normally attached by pelvis to shoulder- 

 girdle, usually with a spine and five rays, sometimes absent, some- 

 times without spine or with many rays, or otherwise modified. 



The great majority of living fishes belong to this group, repre- 

 sented by usually very incomplete fossils. As it is impossible to 

 limit or define the present assemblage of fishes by any special 

 one or group of characters, not only as comparatively few of 

 these have been examined, and therefore the necessary data is 

 not available, most likely their genetic relations may never be 

 demonstrated, and this is due in large measure to the meager 

 palseontological record. The transition of forms is quite variable 

 from those with characters approaching- the Haplomi to those 

 more typical of the spiny-rayed series. About 27 sub^-orders have 

 been defined. 



Sub-Order PERCESOCES 



Branchial arches well developed, bones all present except fourth 

 superior branchihyal. Third superior pharyngeal much enlarged. 

 Lower pharyngeals distinct. Scales cycloid. Spinous dorsal 

 usually present. Pectorals elevated, about level with upper hind 

 opercle angle. Ventrals I, 5, abdominal. 



About six families, two of which are entirely extinct, have been 

 included in this group. The existing forms mostly fresh-water or 

 shore fishes of small size, though many quite large and voracious. 



Family SPHYfkENID/E. 



THE BARRACUDAS. 



Body elongate, subterete. Head long, pointed, pike-like. Jaws 

 elongate, lower considerably projecting. Upper jaw nonpro- 

 tractile, its border formed by premaxillaries, behind which are 

 broad maxillaries. Large sharp teeth of unequal size on both 

 jaws and palatines. No teeth on vomer, usually a very strong 

 sharp canine near tip of lower jaw. Opercular bones without 



