17 
AviCUI.OrECTEN, SJJ. 
(Plate XII, Pig. 1.) 
Observations. — We figure for reference purposes an impel feet east of 
a rig'lit valve, in outline and form of aurieles resemliling A. Sprenti. The 
costte, however, arc of one order, simjde, or occasionally hifurcate. The 
surface is depressed convex, the anterior auricle large, triangular, with five 
very strong radiating costae, and the posterior small and rectangular. The 
anterior and posterior slopes are steep, and sharply separate the auricles from 
the general plane of the valve. 
We at first took this to be A. Sprenti, hut the nature of the costae 
quite forbids such a union, and we can only conclude that the two shells 
are distinct, hut the material in our hands is not sufficient to enable us to give 
a complete and satisfactory description. 
We have two examples of this form, both internal casts, hut neither 
show the slightest indication of costal spines when in the testiferous 
condition. 
Locality and Horizon. — Half mile from Lochinvar Station (C. Cullen ). — 
Permo-Carhoniferous — Lower Marine Series. 
Collection. — Mining and Geological Museum. 
Aviculopecten Engleiiardti, sp. nov. 
(Plate IX, Figs. G-ll ; PI. XI P, Figs. 6-S.) 
Aviculopecten elongatus, De Koninek (lion McCoy), Pccli. Foss. Pal. Nouv.-Galles dii Slid, 
Pt. 3, 1877, p. 15"), t. 22, f. 5. 
Specific Characters. — Shell orbicular, but inequilateral, produced 
anteriorly, sometimes somewhat obliquely so ; slightly inecpiivalve ; valves 
C(pially convex ; cardinal margins sliorter than the wddth of the valves ; uml)o 
of the left valve higher and more prominent tlian that of tlie right ; anterior 
dorso-lateral margins long, ohli(|ue, straight, suddenly rounding-ofi into the 
combined semicircular anterior ventral and ventral margins ; posterior 
margins rounded throughout ; anterior auricles small, narrove, and triangular, 
the outer margins obliquely rounded, divided-off by narrow, well-marked 
byssal notches, and each hearing one strong diagonal ridge, dividing the 
