-:>^ 



CLASSIFICATION Of VERTEBRATES. 



Gasterosteid-E : bodv naked or with bony plates : dorsal with spines : 

 teeth sharp, in jau s alone ; anal with one spine : fresh and brackish 

 water. GasUrosUiu. Aptltes. srxklebacks. Centriscid^, two dorsals, the 

 first spiny: marine. FiSTi'LARiiD^E. bony plates are present; the dorsal is 

 without spines : snout produced into a tube : the species are marine. Fistii- 

 laria has persisted since the eocene. The extinct Dercetidj; iBelonor- 

 hytuhus, Saurorhamphus from the cretaceous i show relations towards 

 Belonc. 



ORDER V. LOPHOBRAXCHII. 



Teleosts with hemibranch ances- 

 tr}' : bodv armored with segmented 

 bony armor : snout elongate : tooth- 

 less : operculum a single plate ; gills 

 composed of small rounded tufts : 

 air-bladder simp'.e, physoclistous : 

 shoulder girdle connected with the 

 cranium. 



SOLENOSTO.MID-E. large gill openings : 

 two dorsals and ventral fins. Solenorhyn- 

 cJius. eocene : Solcnosloina. eocene of Europe 

 and Pacific Ocean to-day. The females carrv 

 the eggs and \ our.g in a brood pouch formed 

 by the ventral rins and the abdominal or cau- 

 dal surface. Svgnwthid.e. appears in the 

 middle tertiary: gill opening very srr.all ; a 

 single dorsal fin and the ventrals absent. 

 Sygnatlius and Sipiiostoma, pipe-fish, have 

 a caudal fin. In Hippoca!>:pus, sea-horses, 

 the tail is prehensile and the caudal ab- 

 sent. 



Fig. 250. Sea-horse, Hip/ - 

 cj m * us ie^'i'iWi nus , after Goode. 



ORDER VI. ACAXTHOPTERYGII (AC-\XTHOPTERI I. 



Gilis laminate; ctenoid or cycloid scales; premasillaries 

 forming the border of the mouth ; shoulder girdle connected to 

 the cranium by a (^usually forked) post-temporal ; ventrals gen- 

 erally far forward, usually attached to the shoulder girdle bv 

 means of the pelvis : the anterior rays of pectorals, ventrals. 

 dorsal or anal fins, usually osseous spines. Here belong the 

 great majority of marine teleosts. Judging from vertebral char- 

 acters and the suspension of the pectoral girdle, they have prob- 



