FIGURE Hb. Magellania Wyvillii Davidson. 



FIGURE lid. Magellania flavescens Lamarck. 



FIGURE He. Magellania kerguelenensis Davidson. 



FIGURES E6, F6, Gb, He. Ontogeny of Magellania (Neoihyris) len- 

 ticularis Deshayes, from the magadiform to the magellaniform stages. 



FIGURES EC, Fc, Gc. The magadiform, magaselliform, and terebratelli- 

 form stages of Terebralella cruenta Dillwyn. 



FIGURES Ed, Fd, Gd. The same stages in Terebratella rubicunda 

 G. B. Sowerby. 



FIGURE E. Magas pumilus Sowerby; the Cretaceous prototype of 

 this structure. 



FIGURES E/, Fe. The magadiform and magaselliform stages of Mag- 

 asella Cumingi Davidson. 



FIGURE t>b. Megerlina Lamarckiana Davidson ; adult form of 

 brachial supports. 



FIGURE Cb. Kraussina rubra Pallas ; adult ; showing septum and 

 two branches. 



FIGURE Cc. Kraussina pisum Valenciennes apud Lamarck. 



FIGURE Cc?. Bouchardia rosea Mawe; adult; showing thickened 

 cardinal process, hinge-plate, and ring on the septum as in Ca. 



