THE FAMILY CGELACANTHINI. 43 



If this supposition should be borne out by the examination of 

 more perfect specimens of Undina, the genera of Coelacanths would 

 be reduced to three, — Ccelacanthus, Holophagus, and Macropoma ; 

 and, in the ornamentation of its scales and fin-rays, Holophagus 

 would occupy the same intermediate position between the other two 

 genera as it does in time. However, it is better, for the present, 

 to retain Undina as a distinct genus. 



Bearing in mind the range of the Coelacanths from the Carbo- 

 niferous to the Chalk formations inclusive, the uniformity of 

 organization of the group appears to be something wonderful. 



I have no evidence as to the structure of the base and side 

 walls of the skull in Ccelacanthus, but the data collected together 

 in the present Decade show that, in every other particular save 

 the ornamentation of the fin- rays and scales, the organization 

 of the Coelacanths has remained stationary from their first recorded 

 appearance to their exit. They are remarkable examples of 

 what I have elsewhere termed " persistent types," and, like the 

 Labyrinthodonts, assist in bridging over the gap between the 

 Palaeozoic and the Mesozoic Fauna?. 



