the Palaeozoic Bivalved Entomostraca. 221 



this little group of specimens do not permit us to divide these 

 different conditions, even as varietal, as they really point to an 

 identity with Primitia umbilicata aforesaid. 



Figs. 6 c and 6 d represent some associates of P. umbilicata 

 in the specimen belonging to the Worcester Museum, and 

 were at first thought to be possibly varieties of the foregoing ; 

 but their more oblong profile, the relatively higher position of 

 the pit, and its being continued upward as a dorsal sulcus, 

 clearly place these specimens, though differing somewhat in 

 relative height (or breadth) , in an already described species, 

 our P. renulina (Ann. Nat. Hist. I. c. fig. 5). 



A suboval Primitia also occurs in the same morsel of fossili- 

 ferous shale, and seems to be (though not fully exposed) P. ovata, 

 J. & II . (Ann. Nat. Hist. I. c. fig. 13), hitherto known only in 

 the drifted Scandinavian limestone. 



We also recognize an oval Primitia in a sandy micaceous 

 shale of the Upper Ludlow series, abounding with small 

 Brachiopods, from Newton Lane, Bradnor Hill, given to one 

 of us some years back by the late Mr. R. Banks, of Kington. 

 It is larger and more oblong-oval than the figured specimen of 

 P. ovata ; but otherwise it seems to be of the same species. 



We may here refer to the existence of two small Primitia} 

 in the Olenus-shales of Shineton*. These we observed in the 

 Cambridge Museum, when examining Prof. M'Coy's Cythere 

 Aldensis preserved there (Ann. Nat. Hist. ser. 4. vol. ii. p. 60). 



Fisr. c>. 



Figs. 6 & 7. Primitia in the Shineton Shales. Cambridge Museum. 

 (Magnified about 20 diameters.) 



They are casts, and are shown by woodcuts, figs. 6 & 7, but 

 do not exhibit sufficiently definite characteristics for exact 

 determination. The larger one (fig. 7) is about -^ inch long, 

 4 high and somewhat resembles our P. matutina (Ann. Nat. 

 Hist, ser.' 3. vol. xvi. p. 418, pi. 13. fig. 7). 



* The " Shineton Shales " are mentioned by Mr. Salter, in the ' Geolo- 

 gical Magazine,' vol. iv. p. 203 (May 1867), as the lowest beds at the 

 Wrekin, and equivalent to " the top of the Llandeilo Flags proper." 

 Shineton or Sheinton is three miles and a half north by west from Much- 

 Wenlock, Shropshire. 



Ann. & Mag. N. Hist. Ser. 4. Vol. iii. 16 



