130 



VERTEBRATE ZOOLOGY 



The more important anatomical characters of Polypterus and its 

 allies are as follows: 



PC/ 



FIG. 70. Crossopterygii. A, Polypterus senegalus; s, position of spiracle (after 

 Bridge). B, Calamichthys calabaricus (after Bridge). C, Larva of Polypterus sene- 

 galus, showing characteristic attitude when resting on the bottom, and the large ex- 

 ternal or cutaneous gills (after Budgett). D, Lateral view of cranium of Polypterus. 

 a, angulare, ar, articulare ; d, dentary ; e, ethmoid ; /, frontal ; m, maxillary ; n, 

 nasal; p, parietal; pm, premaxillary ; po, post -orbital ; q, quadrate; st, supra- 

 temporal ; y, cheek plate ; z, row of small spiracular ossicles. (After Traquair.) 



1. Endoskeleton. The cartilaginous skeleton is largely ossified, 

 the chondrocranium being divided into a number of distinct bones. 



