878 Report oF THE State GEOLOGIST. 
growth of the lateral portions the shell becomes bilobed, the two 
lobes inclosing a perforation situated posteriorly in the median 
line. Loop short. 
Fie. 539. Pygope diphya, Colonna (sp.). CWoopwarp). 
Type, Pygope diphya, Colonna (sp.). 
Distribution. Jurassic. 
Propygope, Bittner. 1890. 
Shells small with the naviculoid contour of AvLacorH. Ris but 
with a short loop. Dental plates absent. Brachial valve with 
a short median septum. 
Fias. 540-543. Propygope Hagar, Bittner. (BiTTNER.) 
Type, Propygope Hagar, Bittner. 
Distribution. Trias. 
Subgenus Zugmayeria, Waagen. 1882. 
Shells biplicate; loop short; with strong dental plates and 
without crural plates. 
Se me 
peek td 
eels! _ Frias. "544-547. Zugmayeria rheetica, Zugmayer (sp.). (ZUGMAYER ) 
vi Nd . 
Type, Zugmayeria rhatica, Zugmayer (sp.). 
Distribution. Triassic. 
130 
