130 



VERTEBRATE ZOOLOGY 



The more important anatomical characters of Polypterus and its 

 allies are as follows: 



J^ 



Fig. 70. — Crossopterygii. — A, Polypients senegalus; s, position of spiracle (after 

 Bridge). B, Calamichthys calabaricus (after Bridge). Larva of Polypierus 

 senegalus, showing characteristic attitude when resting on the bottom, and the 

 large external 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; 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. 



