1G2 ON PERMIAN ENTOMOSTRACA FROM 



Cythere (Bairdid) curta. Jones, in " King's Monog. 

 Perm. Foss.," p. 61, pi. 18, figs. 8a, 3b, 3c. (Not 

 Bairdia curta, M'Coy.) 

 Carapace sub-triangular, convex, smooth, sometimes faintly 

 punctate ; dorsal border arched ; ventral sinuous ; anterior 

 extremity produced, rounded on its ventral half, slightly 

 sinuous dorsally; posterior broadly angular, its angle 

 nearly equal and median; dorsal aspect narrow, acute, 

 oval; a/iimor compressed, oval. 

 This form agrees with B. plebeia, var. caudata, in the curved 

 cultrate border of the anterior ventral region, so characteristic of 

 the species ; but it presents a strong contrast to the above-men- 

 tioned variety, in its being curtailed posteriorly. 



10. C. (Bairdia) plebeia, Reuss. Var. rhombica. PI. XI., figs. 



10, IJ, Ua, I2b. 

 We have here a variety of B. plebeia, in which the long 

 anterior dorsal slope, the obtuse and nearly equal-angled pos- 

 terior extremity, and the nearly straight ventral margin, passing 

 into the broad but not prominent hatchet-edge of the front 

 ventral region, give a rigid and near rhomboidal aspect to the 

 carapace. This, at least, is the chief feature in fig. 10, and figs. 

 11 and 12 are placed with it, as differing but little from it ex- 

 cept in size. 



11. C. [Bairdia) plebeia, Reuss. Var. grandis. PI. XI., figs. 



13cf, 13&. 

 Cythere (Bairdia) curta, Jones, in " King's Monog. 

 Perm. Foss.," p. 64, pi. 17, figs. 21, 22. (Not 

 Bairdia curta, M'Coy.) 

 A single cast (from Humbleton), indicates a Bairdia of twice 

 the size of the common specimens ; but it offers nothing but its 

 greater size to distinguish it from the smaller forms. It is 

 not very dissimilar to B. affinis, Morris, " Ktrzelecki's Phys. 

 Descript. New South Wales, &c." p. 291, pi. 18, fig. 10. 



12. C. (Bairdia) ampla, Reuss. PI. XL, figs. 14a, 14^, 14c. 



