﻿1086 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  Ismenia, 
  King. 
  1850. 
  

  

  Shells 
  coarsely 
  plicate 
  with 
  low 
  umbones, 
  large 
  foramen 
  and 
  

   no 
  cardinal 
  area. 
  Loop 
  with 
  descending 
  and 
  ascending 
  branches 
  

   coalesced 
  with 
  the 
  median 
  septum. 
  The 
  descending 
  branches 
  

  

  Figs. 
  614-616. 
  Ismenia 
  pectunculoides, 
  Schlotheim 
  (sp.). 
  (Quenstedt.) 
  

  

  form 
  a 
  ring 
  whose 
  anterior 
  margins 
  are 
  fimbriate 
  and 
  are 
  pro- 
  

   duced 
  into 
  two 
  fimbriate 
  anterior 
  extensions. 
  

  

  Type, 
  Ismenia 
  pectunculoides, 
  Schlotheim 
  (sp.). 
  

  

  Distribution. 
  Jurassic. 
  

  

  Megerlina, 
  Deslongchamps. 
  1884. 
  

  

  Shells 
  exteriorly 
  as 
  in 
  Muhlfeldtia; 
  the 
  loop, 
  however, 
  differs 
  

   in 
  the 
  abbreviation 
  of 
  the 
  descending 
  lamellae, 
  the 
  anterior 
  por- 
  

   tions 
  being 
  attached 
  to 
  the 
  median 
  septum, 
  and 
  the 
  crural 
  pro- 
  

  

  M 
  

  

  mm 
  

  

  

  Figs. 
  617-619. 
  Megerlina 
  Lamarckiana, 
  Davidson 
  (sp.). 
  (Davidson 
  ) 
  

  

  cesses 
  not 
  united. 
  The 
  anterior 
  attachment 
  of 
  the 
  ascending 
  

   lamellae 
  to 
  the 
  septum 
  is 
  also 
  modified 
  or 
  incomplete. 
  

  

  Type, 
  Megerlina 
  Lamarchiana, 
  Davidson 
  (sp.). 
  

  

  Distribution. 
  Eecent 
  (South 
  Africa 
  and 
  Australo-Zealandian 
  

   Provinces). 
  

  

  144 
  

  

  