the Paleozoic Bivalved Entomostraca. 55 
Malverns and elsewhere, described in the‘ Annals Nat. Hist.’* 
ser. 3. vol. xvi. (1865), pp. 414-425, pl. 13, we have a clearer 
view of the probable relationship of some of these specimens 
from Kildare; whilst others of them fall into the groups of 
Cythere and Bairdia, as recognized by the shape of the cara- 
pace-valves. Primitia is a characteristically Silurian genus t 
(see Ann. Nat. Hist. 7. c.); and now Cythere and Bairdia are 
shown to have existed at that early period, judging from fossil 
carapaces, such as already have been accepted as evidence of 
the persistency of these genera from the Upper-Paleozoic 
(Carboniferous) times to the present day. 
1. Primitia Maccoyiit, Salter, sp. Pl. VII. figs. 1 a-c, 
2ad&b, 3 a-e. 
Cythere phaseolus, M‘Coy (not of Hisinger), Synops. Sil. Foss. Ireland, 
1846, p. 58. 
Cythere Maccoyii, Salter, in Morris’s Catal. Brit. Foss. 2nd edit. 1854, 
p. 105. 
Cythere Maccoyv, (“ Forbes, n.s.?”), Baily, Descript. Quarter-Sheet 
35 N.E. Geol. Surv. Ireland, 1858, p. 10. 
Cythere? phaseolus§ (M‘Coy, not of Hisinger), Salter, in Murchison’s 
‘Siluria,’ 2nd edit. 1859, p. 538, and 3rd edit. 1867, p. 517, 
Carapace like a bean, smooth, subovate, swollen in the 
middle and equally compressed at the ends ; somewhat Leper- 
ditioid in outline, having a nearly straight dorsal line and 
slightly sloping antero- and postero-dorsal margins, and being 
somewhat narrower at one extremity than at the other. Dorsal 
profile acute-oval (in some specimens rather acute-ovate). At 
the middle third of the hinge-line the edge of each valve is 
suddenly depressed, and the boundary of the inflection is 
rounded in the young and slightly ridged in the old specimens. 
The ventral border of each valve is thickened with a rim, 
which is doubled in large and aged individuals. 
* In this paper on Primitie, at p. 417, the name “Schrenk” is twice 
printed by mistake for Schmidt; also in the footnote at p. 424, 
+ To the already recorded Primitie (Ann. Nat. Hist. /. c.) we wish to 
add two, namely, (1) Cytheropsis rugosa, Jones (Ann. Nat. Hist. ser. 3. 
vol. i. p. 249, pl. 10. fig. 5, figured upside down) from the Trenton Lime- 
stone of Canada, which in shape much resembles Primitia senucircularis, 
J. & HL, whilst its punctation is such as we see in P. variolata, J. & H.; 
(2) Leperditia Solwensis, Jones, a very small Leperditioid Entomostracan, 
without eye-tubercle or muscle-spot, from the Lower Lingula-flags, of 
Upper Solva, on the west side of Solva Harbour, near St. David’s, South 
Wales (see Annals Nat. Hist. ser. 2. vol. xvii. p. 95, pl. 7, fig. 16; and 
Quart. Journ. Geol. Soc. vol. xx. p. 288). 
{ For the relative sizes of the Primitie &c. described in this paper, see 
further on, page 58. q 
Specimens from the Chair of Kildare are also referred to, in the 
‘Catal. Collect. Fossils Mus. Pract. Geol.’ 1865, p. 7, as “ Cythere phaseo- 
lus, case 7, tablet 37, specimen 15,” 
