27. LEPIDOSTEIDJL. 
89 
Bnttichiostegals present. Coronoid bone and prjecoracoid arch present. 
Arterial bulb with several pairs of valves. Optic nerves forming a chi- 
asma. I ntestine with a spiral valve. Air-bladder cellular, lung-like, con- 
nected by a sort of glottis with the oesophagus. Tail heterocercal. Skin 
covered with scales, which are ganoid or cycloid. As here understood, 
this group consists of the two orders Ginglymodi and Halecomorphi, 
the Crossopterygia being considered as forming a distinct subclass. The 
Chondrostei, llolostei, and Crossopterygia form the series or subclass 
Gamidei^ represented by five widely divergent families among recent 
fishes and by a great variety of extinct types. These forms, so far as 
known, agree in a number of respects already indicated, and differ from 
all the Teleostei, or ordinary fishes, in the presence of several i)airs of 
valves ill the arterial bulb, and in the presence of the optic chiasma. 
The relations of the Halecomorplii with the Teleostean order of Isospon- 
dyli are, however, undoubtedly very close. 
(Ganoklei Holostei part Giintlier, viii, 324-325, 328-331. 
bone.) 
ANALYSIS OF ORDERS OP HOLOSTEI. 
62 . 0 ^, complete ; oareov, 
*Vertebr® oiiistboccelian ; maxillary bone transversely divided into several pieces. 
Ginglymodi, I. 
** Vertebrie ampbicoelian ; maxillary bone not transversely divided. 
* Halecomorphi, J. 
Oedee I.-GINGLYMODI. 
{The Gar Fihes.) 
Parietals in contact. Pterotic, basis cranii, and anterior vertebrie 
simple. Symplectics present. Mamlible with oiiercular, coronoid, an- 
gular, articular, and dentary bones. Third superior pharyngeal small, 
lying on fourth. Upper basihyal wauthig. Maxillary transversely 
divided. A cartilaginous prmcoracoid arch. Vertebrae opisthocoelian. 
Pectoral fins with mesopterygium and five other basal elements. Tail 
heterocercal. This order includes the single family Lepidosteidce. 
{yiyykuixoqj hinge J oduhq^ tOOth. 
Family XXVIL— LEPIDOSTEID^. 
{The Gar Pikes.) 
Body elongate, subcylindrical, covered with hard, rhombic, ganoid 
scales or plates, which are' imbricated in oblique series running down- 
ward and backward. Both jaws more or less elongate, spatulate or 
beak-like, the upper jaw projecting beyond the lower. Premaxillary 
