138 NEWTON : ALECTRYONIA UNGULATA IN S.E. AFRICA. 
1889.—ALECTRYONIA UNGULATA, R. B. Newton: Quart. Journ. 
Geol Soc, vols pxlv., pli aaa iicemmes 
Pp. 333 (Madagascar), 
DESCRIPTION OF SPECIES. 
Sigmoidal, narrow, elongate, ungulate, mostly smooth in 
the young state; valves with a convex aliform expansion on 
the inner sides near the hinge area, closely ridged with arched 
plications ; the upper or dorsal surface bears a smooth median 
groove which extends along the entire length of shell, and is of 
the same width throughout, and sometimes rather concave; the 
buccal view presents from eight to sixteen (according to age) 
prominent saw-like teeth, which are pointed or obtuse; the 
teeth on the opposite side are not quite so prominent, being 
rather less in size and closer together; the outer sides are 
furnished with long, straight, and broad plications, directed 
obliquely, which are relieved by deeply excavated grooves; 
valves are obliquely convex outwardly and vertically sided 
within, after leaving the expansion ; in the very young state the 
valves are depressed and possess few dentiform plications. 
ALECTRYONIA UNGULATA.—Nat. size. 
From the Upper Cretaceous beds of Sofala. 
The left hand figure exhibits the aliform expansion, groove and lateral plications; the 
other figure gives the buccal view, 
J.C,, viii., Jan. 1896, 
