4 JURASSIC! FAUNA. 



THE FAUNA OF THE KELLAWAYS OF MAZAR DRffi 



IN BALUCHISTAN. 



I— MOLLTISCOIDEA. 



Class: BRACHIOPODA, Cijviei?. 



Sub-class: ARTHRa^OMATA, Owen. 



Order: TELOTBEMATA, Beecber. 



Sub-order: ANCYLOBRACHIA, Gray. 



Family : TEEEBRATUMDjS, Gray. 



Sub-family : TEREBRATULIN^E, DalU 



Genus: TEREBRATULA, Llbwyd. 



Tbbbbratula ventkicosa Zietbn. Plate I, fig. 1-16, •2-2a, 3-35. 



(Synonyms: PaWontologie fran?aise, Terrain jurassiqnes, BraohiopodeB, p. 260, pi. 73, fig. 2, pi. 74, 76.) 



Dimensions. 



length ^^"'■°- 



Breadth ^^ " 



Thickness ^^ " 



The oval shell is considerably longer than broad, its greatest breadth being 

 towards the middle of the length. Both valves are somewhat inflated near the 

 cardinal margin, and depressed towards the frontal region. Beak thick, rounded 

 and truncated with a large foramen, deltidium small, almost hidden by the pro- 

 minence of the beak, lateral ridges indistinct. Marginal line slightly curved and 



raised in front, 



Surface smooth, showing only irregular striae of growth, but occasionally 

 numerous longitudinal striae are visible, due to shell structure. 



Looq,lity and stratiQraphical position.— M&zikX Drik and Sembar Pass, Poly 



P^ewMS-limegtone. 



.Ee?Mffr^».-^This speqies is v^ry common at both localities, but it seems that 

 it never attains a particularly large size. Apparently the mesial fold of the ventral 

 valve varies but little, and generally remains rather flat. 



The specimens from Baluchistan agree in their shape so well with Deslong- 

 champs' fig. 3, or with Davidson's Terebratula buekmani, var. buckmaniana, that I 

 have not the slightest doubt that they must be referred to either one or other of 

 these species, unless M. Deslongchamps' view that both forms are identical is ac- 

 cepted. I fail to discover any difference between these two species, and therefore 

 fully agree with M. Deslongchamps, who considers Terebratula buokmani, Dav., to 

 be identical with Terebratula ventricosa, Ziet. 



