A. R. Foord — Western Australian Fossils. 147 



straighter binge-line, the lesser prominence of the beak of the ventral 

 valve, and tbe more quadrate form of the shell. 

 Locality. — Gascoyne River. 



Spirifera Musakheylensis, 1 Davidson, var. Australis, var. nov. 

 Plate VII. Fig. 2, and ? Plate V. Fig. 12. 



1846. Spirifer fasciger, von Keyserling, Wissensch. Beobacht. auf einer Reise in 

 das Petschoraland im Jahre 1843, p. 229, Tab. viii. tigs. 3, 3a, 3b. 



? 1860. Spirifer tegulatus, Trautschold, Nouv. Mem. de la Soc. Imp. desNat.de 

 Moscou, torn. xiii. p. 354, "Die Kalkbriiche von Mjatschkowa," Taf. 

 xxxv. figs, a — g. 



1862. Spirifera Moosakhailensis, Davidson, Quart. Journ. Geol. Soc. vol. xviii. 



p. 28, pi. ii. fig 2, a— c. 



1863. Spirifera Moosakhailensis, de Koninck, Fossiles Paleoz. de l'lnde, p. 34, 



pi. xi. figs. 2, a — c (copied from Davidson's, loc. cit.). 



1865. Spirifer Moosakhailensis, von Martens, in Beyrich, Physik. Abbandl. der 



Konigl. Akad. der Wissensch. zu Berlin (1864), Ueber eine Kohlenkalk- 

 Fauna von Timor, p. 77, Taf. i. fig. 7. 



1866. Spirifera Moosakhailensis, Davidson, Quart. Journ. Geol. Sec. vol. xxii. 



p. 41, pi. ii. fig. 5. 

 1887. Spirifer Musakheylensis, Waagen, Pal. Indica, Ser. xiii. Salt Range Fossils, 



vol. i. p. 512, pi. xlv. 

 1889. Spirifer fasciger, Tschernyschew, Allgcm. geol. Karte von Russland, Blatt 139, 



(Mem. du Com. Geol. vol. Hi. No. 4), pp. 353, 366, Taf. v. figs. 4, a— c. 



The following is Davidson's description of this species : — " Shell 

 transversely rhomboidal ; valves almost equally deep or convex ; 

 hinge-line variable in length, sometimes not half as long as the 

 breadth of the shell, while at times it is as long. Ventral area of 

 moderate width ; fissure wide and partially covered over by a pseudo- 

 deltidium. Dorsal valve sub-linear; beak small and moderately in- 

 curved. In the dorsal valve there exists a wide, elevated angular fold, 

 and in the ventral one a corresponding sinus. The whole surface of 

 the shell is covered with numerous small ribs, which cluster into fasci- 

 culi, seven or eight being collected into groups, which give to the 

 valves the appearance of a double plication, many of the smaller ribs 

 being due to interpolation ; while the whole surface and ribs are 

 closely intersected by numerous sharp, projecting, concentric un- 

 dulating lamina?, of which four or more may be counted in the 

 breadth of a line. Dimensions very variable : a large example 

 measured 26 lines in length by 39 in width and 18 or 19 in depth. 



It was not until after much hesitation that I have ventured to 

 propose a new name for the Spirifera under description. In 

 external shape as well as by the grouping of the ribs it bears much 

 resemblance to several known species of Spirifera, and especially to 

 that figured in Owen's " Geol. Survey of Wisconsin and Minnesota " 



p. 229, Tab. viii. figs. 2 a— c (1846). See also de Koninck, Faune du Calc. Carb. 

 de la Belgique, 1887 (Ann. du Mus. Roy. d'Hist. Nat. de Belgique, torn, xiv.), 

 pt. vi. p. 108, pi. xxiv. figs. 6, 7, and pi. xxvi. figs. 1 — 4. Recorded also by Th. 

 Tschernyschew, Allgem. geol. Karte von Russland, Blatt 139 (Mem. du Com. Geol. 

 vol. iii. No. 4), p. 355. 



1 This word is written "Moosakhailensis" by Davidson, but I have adopted 

 Waagen's spelling of it (Salt Range Fossils, Pal. Ind.), as being doubtless the more 

 correct one. 



