892 Report oF THE State Groxoaist. 
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 
Fias. 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, /smenia pectunculoides, Schlotheim (sp.). 
Distribution. Jurassic. 
Megerlina, Deslongchamps. 1884. 
Shells exteriorly as in Miiatretprra; the loop, however, differs 
in the abbreviation of the descending lamella, the anterior por- 
tions being attached to the median septum,’and the crural pro- 
Fies. 617-619. Megerlina Lamarckiana, Davidson (sp.). (Davipson.) 
cesses not united. The anterior attachment of the ascending 
lamelle to the septum is also modified or incomplete. 
Type, Megerlina Lamarckiana, Davidson (sp.). 
Distribution. Recent (South Africa and Australo-Zealandian 
Provinces). 
144 
5 
| 
; 
1 
