58 Prof. T. R. Jones and Dr. H. B. Holl on 
1. Bairdia Murchisoniana, sp.nov. Pl. VIL figs. 9a, 9. 
Carapace smooth, almost subcylindrical, arcuate, tapering, 
and compressed at the ends. Anterior end rounded obliquely, 
posterior obtusely pointed. Dorsal profile narrow and acutely 
oval, Rare. 
This elegant Bairdia, resembling to some extent other 
elongate forms of Bairdia, but wanting the broadly produced 
and hatchet-shaped anterior end of the Carboniferous and 
Permian B. curta and its varieties*, is dedicated to Sir R. I. 
Murchison, Bart., whose Silurian researches have so greatly 
aided in elucidating the structure and history of the old rocks 
of Ireland, as well as of Great Britain and many other parts 
of the world. 
2. Bairdia Griffthiana, sp.nov. Pl. VII. figs. 10 a, 10 d. 
Carapace smooth, subdeltoid; back obliquely arched, with 
steep unequal slopes to the extremities, the anterior of which 
makes an acute angle with the ventral border, whilst the pos- 
terior is obtusely rounded. Ventral border slightly sinuate. 
Ventral profile acute-ovate, compressed. Rare. 
The name of Sir Richard Griffith, Bart, the veteran Geolo- 
gist of Ireland, is attached to this species. 
3. Bairdia Salteriana, sp.nov. Pl. VII. figs. 11 a, 11. 
Carapace smooth, swollen, subovate; with angular com- 
pressed ends, and an acute-oval profile. Rare. ‘l’o some ex- 
tent this species resembles a subrhombical variety of B. plebeta 
(see ‘‘ Permian Entomostraca,” in the Transact. ‘Tyneside Nat. 
Field-Club, vol. iv. pl. 11. fig. 12 a). 
Named in honour of J. W. Salter, Esq., F.G.S., whose re- 
searches among Silurian Fossils are well known. 
Measurements. 
Length. Width. Thickness. 
inch. inch. inch. 
Primitia Maccoyii, old ...... 0-09 0-0575 0-045 
rs a5 intermediate| 0-07 0:0525 
rr young ....| 0°0375 | 0025 0:02 
Sancti-Patricii...... 0:05 0:04 0:025 
Cythere Wrightiana ........ 00675 | 0:0325 0:0275 
Pi Baily 2a oostiaeopetae OO56 sl oncee 0-015 
ya, SUReSANA 5 6 cscs es 0:07 0:0275 00225 
Pr) blarkmessiaria.ycite ss 0:0575 0:0325 0:03825 
Bairdia Murchisoniana ...... 0:0525 0:0225 0:0175 
yy OREM Naas. ee seh 0-04 0:0225 nearly | 0-015 to 0:0175 
yy o allterianiar 2, oe an 0-045 0:0225 0:0225 nearly 
* Ann. Nat. Hist. ser. 3. vol. xviii. p. 42. 
