FiGUKE Gi. — Terehrataliform staye, with ascending branches attached 

 to ends of di'suending branches. 



FiGUKB III. — Final adult condition of Macandreciii criiniuiii MiiUer; 

 showing absorption of septum and connecting bands from descending 

 branches. 



FiGur.E ir>. — Adult stage of Macdndrevin tenera Jeffreys. 



Ontogeny of Dallina sejJtigera Lovcn 



FiiiUKKs A, B, C'l. — Stages of growth common to all the genera 

 of Dallininir. 



Figure Da. — Late platidiform stage. 



FiGi'KK. K-i. — . Ismenifoim stage. 



Figure Fj. — Mulilfehltiform stage. 



Figure Gi. — Terdiniialifonn stage. 



Figure Ha. — Adult Ihilliiui xepln/ira Loven. 



Figure 114. — Dallinn Ruphaelis l),dl. 



Figure Pis. — D(diinit fluridana Pourtales. 



Figure Ho. — Ddlimn G/w/j Davidson. 



FitURKS Co, Da, E3, F:i. — Ontogeny of Muhlfelilliaaaiii/uiiifa Chemnitz. 



Fkiure Gs. — Terehraliilin coreiinicd .\damsand Reeve; adult structure. 



Fii;uRE F4. — ISlilhlfcldtifonn sta^e of Lm/ueus cidiforrdcus Koch. 



I'iGURE (14. — Adult Laqueua cfdifornicus Koch; showing connecting 

 bands from ascending and descending lamelte. 



Figure G.j. — Lnqncust picliix Chemnitz. 



Figure Ge. — TriiiimosemuK eler/ans Koenig; a Cretaceous representa- 

 tive of the Tercbrataliit structure. 



Figure E4. — Ismeniafurcaln Sowerby; Jurassic. 



Figure E.5. — Isnunin Duel, imuii Moore; Jurassic. 



Figure Cs. — Pliiliilifdnn sta'^e of lJ(d/iii(i Jloi-idana Pourtales V 



Figure C4. — Adult I'lalid'ui anomioides Scacohi. 



Morphogeny of Magki.laniin/e (Pages 293-29.5) 



Ontogeny of Terehralella dorsaia Gmelin, and MageUania renosa Solander 



Figure A. — Gwyniform stage. 



Figure B. — Cislellifurm stage. 



Figure CV/. — Bmw/inrdifor/ii stage, with small ring on septum. 



Figure Ca' — Side view of same. 



FiGUKK Da. — Mefjerliniform stage; showing growth of ring, or 

 ascending branches. 



Figure Y>n'. — Side view; showing growth of descending branches 

 as prongs on side of septum. 



Figure Ki/. — Magadiform stage ; showing completion of descending 

 branches. 



Figure Fa. — I\ragaseUifunu stage; showing union of descending and 

 ascending branches. 



Figure Ga. — Terehralell iform sta,ge-, representing the finished type 

 of struclure in Terehralella dorsaln Gmelin. 



P^iGURE Iln. — Final stage of Mngellnnia venosa Solander; produced 

 by resorption of the septum and connecting bands of the terehrnlelliform 

 stage. 



