218 Prof. T. Rupert Jones — South Wales Entomostraca. 



of very minute hexagonal punctation, as E. Adamsii. In ornament 

 it resembles E. punctatella, Jones, as well as the recent forms men- 

 tioned above, but differs from them materially in shape. 



In the piece of Anthracomyan shale from Ardwick, given me by 

 Prof. W. C. Williamson (see above, p. 217), I also recognize, under 

 the microscope, a morsel of a similar reticulate valve. This Estheria 

 will therefore be found elsewhere. 



In a piece of the shale from Mr. Adams's collection, I observe two 

 specimens of Estheria tenella (Monog. Foss. Esth., p. 31, pi. 1, fig. 

 26, 27, &c.). 



§ 3. C'l/theroid Entomostraca. — There are at least three Cytheroid 

 forms in the shales under notice ; although often crushed, or occurring 

 as mere casts, yet in some instances the valves are well preserved. 

 They differ from known GytTierce, Cyprides, &c., not only in the 

 patterns of the " muscle-spot," but in having the inner face of that 

 spot excavated at its margin, and in having the inner surface of the 

 valves reticulated with vascular impressions, especially near the 

 centre. In such points these old Cytheroids have Leperditian and 

 Beyrichian characters ; but their valves resemble those of CytJiere 

 and other Ostracoda. The very common Carboniferous species, 

 Cythere (?) fabulina, Jones and Kirkby, MS. (Trans. Glasgow Geol. 

 Soc, vol. ii., p. 217, 1867), is an allied form, and probably belongs 

 to the same generic group, which I designate Carbonia. 



1. Carbonia Eoelince, uov. (PI. IX., Fig. 4). — Subovate ; dorsal line 

 divided in unequal thirds by the front and back slopes and the straight 

 hinge-line between. Anterior end sharper than the posterior. Ventral 

 border well curved. Surface wrinkled by numerous small, smooth, 

 rounded ridges, longitudinal, interrupted, sinuous, tapering away 

 amongst themselves, and converging towards the ends of the valves. 

 In the centre of each valve a small circular area or " muscle-spot " 

 is visible, consisting of three or four minute subtranslucent spots 

 crowded together within a darkish circle. The wrinkling of the 

 general surface is continued faintly over these muscle-spots. This 

 species is rare. 



2. Carbonia Agnes, nov. (PL IX., Figs. 6 and 7). — Ovate-oblong ; 

 dorsal edge gently arched, ventral line straight or slightly incurved ; 

 anterior third of the valve rather larger than the posterior. The 

 surface is quite smooth in some specimens, and shows a small central 

 muscle-spot, consisting of a narrow darkish circle, enclosing a light 

 (translucent) area, in which a dark, irregular, four-bodied spot is 

 set, with a few black specks along one of its edges. 



The casts have a faintly reticulated surface, due to the structure 

 of the shell ; and on the casts the place of the " muscle-spot " is 

 indicated by a small round area with a raised ledge, higher on one 

 side than the other. There is also a slight transverse hollow behind 

 and below the central spot on the cast. 



a. Var. subrugulosa. (Fig. 10). — Here the shell has its smoothness 

 partially interfered with by faint longitudinal striae. 



/8. Var. rugulosa (Figs. 8 and 9). — The shell is strongly striated 

 by longitudinal interrupted wrinkles, converging towards the ends 

 of the valves. 



