110 Frederick Cka'pinan : 



ijurface strongly convex; general surface punctate. There is an 

 ocular spot in some specimens situated in the anterior third. 

 Ventral view shows the characteristic infolded margin which in the 

 left valve is overlapped by the right. The end view shows a sub- 

 oval outline. 



JJintensio/is. — Holotype,! length, ,*i mm. ; lieight, 2 mm. ; thick- 

 ness of carapace, 1 nnn. Length of a pnratype (Tate coll.), 4.4. mm. 

 Length of another paratype (Sweet coll.), 2.4 mm. 



Obsfirv"fl(n(s. — From the outline of the above fossil one is re- 

 minded of tlij Cambrian genus Ahifa, especially A.enyo^ Walcott 

 sp.2 The carapace in the South Australian species, however, is not 

 <'ontinuously rimmed by a flange, and is not so uniforndy com- 

 pressed. This species is of the general form of Lejyerditia nnna\ 

 Jones, -5 from tlio Calciferous Sandrock (Upper Cambrian) of St. 

 Ann's, at the confluence of the Ottawa and St. LaAvrence, Canada. 

 L.tatei agrees in outline, position of the ocular spot, and the punc- 

 tated shell-surface; L.a/ino differs from L.iatti in having a rounded, 

 not m'^rgined, anterior, a more depre sed and a larger carapace, 

 the length of L.anna being 5 mm. 



Lejyerditia tntei is evidently a veiy abundant form in the Curra- 

 mulka Limestone, for fragments of the carapace are found scat- 

 tered througli it. In his paper on " The Cambrian Fossils of South 

 Australia," Pi-of. Ralph Tate says* that the genus Leperdifia " is 

 indicated by the occurrence of two species, one, which has much 

 resemblance to Tj.dermatnides, Walcott, is oval in outline, and 

 about 3 mm. in the long diameter ; the other has a circular outline 

 with a diameter of about 1 mm. Botli are moderately common, but 

 I have not secured any example of either sufficiently free from 

 Triatrix to permit of a critical comparison with figured species, or 

 to figure with a sufficient degree of accuiacy." The specimens 

 referred to by Tate having 1 eeii kindly lent me by Mr. Walter How- 

 chin, I am in a position to say that the fossil mentioned as having 

 a long diameter of 1 mm., is evidently that now figured as Leper- 

 •drt'ia tatei (paratype, pi. IX., fig. 2); whilst the larger specimen 

 referred to as having an oval outline with much resemblance to 

 L.dermafoides, Walcott is evidently a species of Isochilina. 



Occurrence. — Grey Limestone. Upper Cambrian, Curramulka, 

 S. Australia. Tate and Sweet colls. 



1 Pres. to National Museum coll. 



2 Bradoria fnij«, Walcott, Pro«. U.S. Nat. Miis., vol. x\ix., 190.5, p. 99. Alafa enyo, Walcott 

 «p.. Research in China, vol. iii., 1913, p. 22.o, pi. xxiii., fi^-. 11. 



3 Ann. Maj,'. Nat. Hist., ser. 3, vol. i.. 1858, p. 247, pi. ix,, fig. IS. 



4 Trans. R. Soc. S. .Austr., vol. xv , 1892, p. 1S7. 



