320 RKCORDS OF THE AUSTRALIAN MUSEUM. 



Tlie outline is that of my conception" of Pseudaiv'cida anomala 

 Moore, sp., but out of the immense number of specimens and 

 fragments not one has shown the characteristic sculpture of that 

 species. Indeed, the only trace of ornament on the shell of 

 P. papi/racea is that of a few concentric, almost microscopic lines ; 

 the test is far too thin to carry the well marked decussate sculp- 

 ture of P. aiiomala. 



I believe it to be one of the undetermined valves figured at the 

 reference above. 



The specific name is in allusion to the delicate nature of the 

 test. Figures will be given in a subsequent part. 



Genvs Maccoyklla, Eth. fil., 1892. 

 (Geol. Pal. Q'land, kc, 1892, p. 451). 



MaCCOYELLA CORBIENSIS, Moorc, SJ>. 



(Plate Ixi , figs. 1-6). 



Avicula corbiensis, Moore, Quart. Journ. Geol. Soc, 1870, xxvi., 

 p. 246, pi. xi., f. 7. 



MacGoyella corbie^isis, Eth. fil., Mem. Geol. Survey N. S.Wales, 

 Pal. No. 11, 1902, p. 21, pi. i., f. 6-10 (fo)- synonomy). 



Ohs. — In the phenomenally rich calcereous shale containing the 

 preceding species and Pachydomella chiitus occur a large number 

 of left valves agreeing in every particular with the corresponding 

 valve of M. corbiensis, except in that of size. The maximum 

 measurements of this species are approximately two and a quarter 

 inches in length by two and a half inches in breadth, whereas in 

 the specimens under review the average is about one half of the 

 above; other than by this discrepancy, I am unable to differentiate 

 between the respective specimens. In other words, those collected 

 by Mr. Blomfield are 3f. corbiensis in minature, and seem to 

 represent a dwarf i-ace of the species. Here and there, it is true, 

 are examples with a greater breadth in proportion to length than 

 in M. corbiensis proper, but this cannot be allowed to weigh in 

 the face of more important features. Again, the posterior alation 

 seems to be more highly developed in some examples than in 

 larger individuals from other localities. One -specimen fortunately, 

 although worn externally, has the internal structure admirably 

 preserved, particularly that of the articulus (PI. Ixi., fig. 1). 



8 Etheridge— Mem. E. Soc. S. Aiistr., ii., 1, 1902, pi. ii., f. 1. 



