C, E. Beecher — Development of Terehratalia obsoleta, Doll. 397 



Ontogeny of Dallina septigera Lov^n. 



Figs. A, B, CI. — Stages of growth common to all the genera of Dallininae. 



Fig. D2. — IjSite plaiidiform stage. 



Fig. E2. — Ismeniform, stage. 



Fig. F2. — Muhlfeldtiform stage. 



Fig. G2. — Terebrataliform stage. 



Fig. H3. — Adult Dallina septigera Loven. 



Fig. H4. — Dallina Raphaelis Dall. 



Fig. H5. — Dallina floridana Ponrtales. 



Fig. H6. — Dallina Grayi Davidson. 



Figs. C2, D3, E3, F3. — Ontogeny of Muhlfeldtia sanguinea Chemnitz. 



Fig. G3. — Terehratalia coreanica Ad. and Eve., adult structure. 



Fig. F4. — Miihlfeldtiform stage of Laqueus californicus Koch. 



Fig. G4. — Adult Laqueus californicus, showing connecting bands from ascend- 

 ing and descending lamellae. 



Fig. G5. — Laqueus pictus Chemnitz. 



Fig. G6. — Trigonosemus elegans Koenig, a Cretaceous representative of the Tere- 

 hratalia structure. 



Fig. E4, — Ismenia furcata Sow., Jurassic. 



Fig. E5. — Ismenia BucJcmani Moore, Jurassic. 



Fig. C3. — Platidiform stage of Dallina floridana Pourtales ? 



Fig. C4. — Adult Platidia anomioides Scacchi. 



Morphogeny of Magellaniinse. 



Ontogeny of Terehratella dorsata Gmelin, and Magellania renosa Solander. 



Fig. A. — Gwynifortn stage. 



Fig. B. — Cistelliform stage. 



Fig. Ca. — Bouchardiforni stage, with small ring on septum. 



Fig. Ca'. — Side view of same. 



Fig. Da. — Megerliniform stage, showing growth of ring, or ascending branches. 



Fig. Da'. — Side view, showing growth of descending branches as prongs on side 



of septum. 

 Fig. Ea. — Magadiform stage, showing completion of descending branches. 

 Fig. Fa. — Magaselliform stage, showing union of descending and ascending 



branches. 

 Fig. Ga. — Terebratelliform stage, representing the finished type of structure in 



Terehratella dorsata Gmelin. 

 Fig. Ha. — Final stage of Magellania venosa Solander, produced by resorption of 



the septum and connecting bands of the terehratelliform stage. 

 Fig. Hb. — Magellania Wyvillii Davidson. 

 Fig. Hd. — Magellania flavescens Lamarck. 

 Fig. He. — Magellania kerguelenensis Davidson. 

 Figs. Eb, Fb, Gb, He. — Ontogeny of Magellania (Neothyris) lenticularis Deshayes, 



from the magadiform to the magellaniform stages. 

 Figs. Ec, Fc, Gc. — The magadiform, magaselliform, and terebratelliform stages 



of Terehratella cruenta Dillwyn. 



Trans. Conn, Acad., Vol. IX. July, 1894. 



28 



