Figure Gi. — Terebrataliform stage, with ascending branches attached 

 to ends of descending branches. 



Figure Hi. — Final adnlt condition of Macandrevia cranium Midler; 

 showing absorption of septum and connecting bands from descending 

 branches. 



Figure H-:. — Adult stage of Macandrevia tenera Jeffreys. 



Ontogeny of Dallina septigera Loven 



Figures A, B, Ci. — Stages of growth common to all the genera 

 of Dallininaj. 



Figure Da. — Late platid if arm stage. 



Figure E2. — Ismeniform stage. 



Figure Fa. — Muldfeldtiform stage. 



Figure G2. — Terebrataliform stage. 



Figure Hs. — Adult DaUina septii/cra Loven. 



Figure H4. — Dallina Raphaelis Dall. 



Figure Hs. — Dallina floridana Pourtales. 



Figure He. — Dallina Graj/i Davidson. 



Figures C-2, D3, E3, Fs. — Ontogeny of Muldfeldlia sanijidnea Chemnitz. 



Figure Gs. — Terehralalia coreanica Adams and Reeve; adult structure. 



Figure F4. — Mithlfeldtiform stage of Laqneus adifomicuii Koch. 



Figure G4. — Adult Laqueus californicus Koch; showing connecting 

 bands from ascending and descending lamellae. 



Figure Gs. — Laqueus pictus Chemnitz. 



Figure Ge. — Trigonnsemus elegans Koenig; a Cretaceous representa- 

 tive of the Terehralalia structure. 



Figure E4- — Ismenia f areata Sowerhy ; Jurassic. 



Figure Es. — Lwienia Buchnani Moore; Jurassic. 



Figure Ca. — Platidiform stage of Dallina floridana Pourtales? 



Figure C4. — - Adult Platidia anomioides Scacclii. 



Morphogeny of IMagellaniin.e (Pages 293-295) 

 Ontogeny of Terchratella dorsata Gmelin, and Magellania renosa Solander 



Figure A. — Givyniform stage. 



Figure B. — Cistelliforni stage. 



Figure Ca. — Bouchardiform stage, with small ring on septum. 



Figure Ca'. — Side view of same. 



Figure Da. — Megerliniform stage; showing growth of ring, or 

 ascending branches. 



Figure Da'. — Side view ; showing growth of descending branches 

 as prongs on side of septum. 



Figure En. — Magadiform stage ; showing completion of descending 

 branches. 



Figure Fa. — Magaselliform stage; showing union of descending and 

 ascending branches. 



Figure Ga. — Terebratelliforyn st?ige; representing the finished type 

 of structure in Terebratella dorsata Gmelin. 



Figure Ha. — Final stage of Magellania venosa Solander; produced 

 by resorption of the septum and connecting bands of the terehratelliform 

 stage. 



