184 RECORDS OF THE AUSTRALIAN MUSEUM 



eithei' bv de Koninck or myself. The lateral folds are always conspicuous 

 in median sized specimens, less marked in young examples, but in large 

 individuals it may be either tlie one or the other. In Fig. 3, the lateral 

 folds are hardly perceptible, whereas in Fig. 4, they are decidedly 

 pronounced. D. inversa and D. rijmlxvformis, Morris, appear to be close 

 allies. 



Loc. — Wollongoug (W. S. Dim). 



Hor. — Upper Marine Series. D. inversa also occurs in the Lower 

 Marine Series at Harper's Hill, near Allandale, West Maitland District. 



II. — Genus Martiuiopsis, Waagen., 1883. 



(Salt Range Foss. (Pal. Indica), i., pt. iv., fas. 2, 1888, p. 524.) 



Martiuiopsis strzelecki, de Koninck. 



(Plate xxviii., tig. 1.) 



Martiuiopsis strzelecl-i, de Koninck, Foss. Pal. Nouv. Galles du Sud, pt. 8, 

 1877, p. 97, pi. xiii., figs. 1, la. 



Obs. — The very marked slits left by the dental supporting plates in 

 the pedicle valve and the equally well developed septal plates in the 

 brachial valve, and which combined tend to distinguish Martinioih'<i!< from 

 Spirifera, clearly indicate this species as a member of the former. The 

 fold is remarkably large and produced as compared with the cast figure of 

 the brachial valve given by de Koninck, and is leather an apt illustration 

 of the great variability that occurs in most of our Permo-Carboniferous 

 members of the Spiriferidse. 



The fossil represented in PI. xxviii., fig. 1, 1 regard as an extreme 

 variet}' of those internal casts called by de Koninck Spirifer strzelecki. I 

 restrict my remarks to the internal casts, because it has still to be shown 

 that the testiferous example, figured under the same name, and the cast 

 are one and the same species. 



Attention does not appear to have been called to the remarkable 

 divergence of the Australian Mai'tiniopses in form and other external 

 characters from the typical species described by Dr. Waagen. Had it not 

 been for his hint of the possible generic affinity' of some of our species, 

 then known simply as Spirifera, it is more than probable that the relation- 

 ship would have been overlooked. The form and external appearance of 

 the Indian and Australia)! shells are respectively so very unlike, that wei-e 

 it not for the internal similarity of structure one would be tempted to 

 sepai*ate them. 



Martiniopsis, as constituted by Waagen, was defined as comprising 

 "more or less globular, or thick lenticular, smooth" punctate shells. 

 None of our species are globular, the nearest approach being 3f. orifiir>iiis, 

 McCoy, and all ai-e more or less costate, least apparent, however, in M. 

 subradiata (s.s.). The thick lenticnlai" form may perhaps be found in 3/. 

 subradiata, var. transver.fa, milii.-' The species most commonly met with 



:< Etheridge— Geol. Fal. Q'land, etc., 1892. p. 239. 



