232 VINE: CARBONIFEEOUS ENTOMOSTRA( ;A, ETC. 
figured by Jones & Kirkby. Another specimen shows a slight con- 
cavity on the ventral border. 
The description given by the authors applies " to the more 
typical examples, which are always to be distinguished by their 
nearly straight backs, regularity of height, and well-rounded anterior 
ends." It is very rare, however, that the valves are found uncrushed. 
In the crushed specimens the posterior extremities are more pointed, 
a feature shown in some of the figures of the authors. 
Localities : Richmond ; and Limestone Shales, Hurst. Professor 
T. Rupert Jones and Mr. J. W. Kirkby give a veiy full list of the 
localities of this species from the Upper and Lower Limestones of 
Scotland, but the authors give no locality in England, and only one, 
Great Ormes Head, in Wales. 
3? Bairdia HisiNGERi, Munstei . 
Cythere hislngerl, Munster, 1830, Jahrb. f. Mimi-aloyie, p. Go. 
Bairdia hi slnget'i Jones & Kirkby, 1865, Ann. Mag. Nat. Hist. ser. 3.» 
vol. XV., p. 408, pi. XX., fig. 12. 
Bairdin hisingeri Jones &, Xirkhx, Quart. Jour. Geol. Soc. Nov., 1879, 
pi. XXIX., figs. 4-10, p. 570, pi. XXX., fig. 12.* 
This species, though present in the Yorkshire shales, is not so 
fine nor so common as in some of the Scottish shales. 1 have only 
four fragments of the t^^pical form, one of which shows the peculiar 
muscle spot. I have figured two other examples (figs. 2 and 2a), 
for the purpose of comparison. They are very similar in the general 
contour to those figured by Jones & Kirkby (pi. XXX., figs 12 and 
13, Qimr. Jour. Geol. Soc, Nov., 1879), which the authors consider 
to represent an elongate form of B. Jdsingeri. " Fig. 12 is from 
Campsie," J. & K. 
It is rather more elongate than the Yorkshire specimen, and it 
is less convex in the dorsal border, but the general outline is in many 
respects similar. Both the figures are magnified in the same pro- 
portion, 25 diameters, so that the differences between the two 
specimens may be noted. 
Localities : Limestone shales : Hurst, Richmond. The localities 
in England given by Jones & Kirkby, are from Carb. Limest., River 
Wansbeck, Northumberland ; and Wyebourne, Cumberland. 
* See paper for other SjTionyms. 
