18 
auricle unequally ; posterior auricles very small, flat, ill-defined, their outer 
margins oblique and straight. Sculi)ture of very fine, close, regular concentric 
lilies, crossed by even finer radii, that are only distinguishable by reflected 
light ; latilaminai ivide apart. Hinge-plates linear, and very narrow. 
Ohservalious . — As Avieulopecten elongatiis, He Koninck figured an 
imperfect right valve believed by him to be referable to Pecten elongalns, 
McCoy, ^ of the Irish Carboniferous Limestone, but he appears to have 
overlooked the fact that the latter is an equilateral shell, and is no-t produced 
anteriorly. He Koninck’s specimen lacked the auricles, but the regular 
convex surface, anterior extension, and wide latilamiiue indicate its identity 
with our present figures. 'Fhe latter are obviously allied to Pecten variahilis, 
lMcCoy,“ another Irish Carboniferous form, and in a minor degree to our own 
Carboniferous species, P. ptychotis, iNlcCoy. 
l)r. C. IJicner has figured the left valve of an Aijiculopeclen from the 
Zewan beds of the Kashmir A^alley,^ which is indistinguishable from A. 
PnglehardtL 
The outline, and inclination to anterior obliquity, are features of 
^[cCoy’s genus Slrehloj)teria, but in our S 2 )ecics there is no trace of the 
cardinal tooth Avhich distinguishes that genus, and sejiarates it from the other 
members of the family. Most authors in writing of Steehlopferia appear to 
have entirely overlooked the possession of this tooth. 
It must be noted that the extension of the anterior ends is much 
accentuated by pressure, flattened examples displaying a remarkable 
resemblance to A. variahilis, McCoy, but that this extreme degree of obliquity 
is superindueed is proved by the presence of other uncompressed examples in 
our eollections. Inequality of the valves is markedly exhibited by the 
projection of the umbo of the left valve altove tliat of the right. 
There is a good deal of variability in the relative convexity of the valves 
of one individual as compared wnth those of another. This is exemplified in our 
PI. IX, Pig. 9, a testiferous right A'alve, and PI. XIV, Pig. 6, a similar valve, but 
an internal east. 
' McCojf — Syiiop. Carl). Lime. Fo.ss. Ireland, 1844, p. 92, t. IG, f. 9. 
- McCoy — Hid., p. 101, 1. IG, f. 7. 
* Diener— Himalayan Foss. (Pal. Ind.), 1899, I, Ft. 2, p. 16, t. 1, f. 3. 
