The Austral Rhynchonellacea. 



177 



In this the shell is transversely elongate, the dental 

 plates are short, strong and somewhat curved. The lateral 

 areas have six prominent angular ribs; the median sulcus 

 carries four fainter costae. There are traces of distinct 

 transverse lamellae. We are inclined to think that the two 

 figures represent different species, since the ventral valve 

 (fig. 13) has the deep sulcus and prominent beak of Buck- 

 man's genus KaUirhynchia. Figure 14, if shown by ad- 

 ditional specimens to be distinct, might be re-named 

 Burmirhynchia etheridgei. 



Occurrence. — Cretaceous. Croydon Goldfields, Queens- 

 land. 



PHYLOGENY ofthe AuSTRAL and RELATED RmYNCHONELLACEA. 



■r.t.^osjfc'f--" 





Rhynchonella eyrei, Etheridge, fil., 1902, p. 8, pi. I., fig. 2. 



Triangular; costae prominent and coarse, three to 

 four on fold; two to three on the sinus, and three to 

 four on either side. The valves are crossed by numerous, 

 concentric frilled laminae. 



Occurrence. — Lower Cretaceous. Central South Aus- 

 tralia. 

 Jthynchonella 7'ustica, Moore, 1870, p. 245, pi. X., fig. 79. 



The shell is wider than long, with 20 to 25 costae. 

 The beak is acute and compressed when young. The sur- 



