A EEVISION OP THE BRANOHIOSTOMID^. 323 



Fig. 4. — Ventral and profile views of Amphioxus californiensis, 

 Cooper. In the profile view the prteoral hood is represented as much con- 

 tracted as it is in spirit specimens. 



Fig. 5. — Ventral and profile views of Amphioxus caribseus, Sundevall. 

 In the profile view the prseoral hood is incompletely expanded. 



Fig. 6. — Ventral and profile views of Heteropleuron Bassauum, 

 Giinther. 



Fig. 7. — Ventral and profile views of Heteropleuron cingalense, 

 Kirkaldy. Prseoral hood in the profile view only partially expanded. 



FiG. 8. — Ventral and profile views of Amphioxus Belch eri, Gray. In 

 the profile view the praeoral hood is not nearly so fully expanded as in 

 the ventral view. 



