502 DR WHEELTON HIND ON 



Dimensions. — Fig. 12, PI. I., measures: antero- posteriorly, 26 mm.; dorso-ventrally, 

 20 mm. 



Locality. — Middle Llandovery of Woodland Point. 



Observations. — There are three fairly well preserved specimens which I refer to 

 this species. They seem to me to indicate an approach to a Pecten-like form, more 

 especially to the genus Streblopteria ; but the Pecten-like anterior ear, present in the 

 latter shell, is absent. 



Beushausen (op. supra cit.) suggests that the genus is allied to Cardiola, but I do 

 not see the grounds for this view. All the specimens in the Gray Collection are left 

 valves. 



Genus Sphenolium, Miller, 1889. 

 Sphenolium, Miller, 1889, N. Amer. Geol. and Pal., p. 513. 



Generic Characters. — " Shell large, equivalve, inequilateral, elongate, cuneiform, 

 ventricose. Umbones prominent, beaks incurved at the anterior end. Cardinal line at 

 an angle of 50° or 60° from the basal line, and appearing wing-like towards the 

 posterior end. Lunule present ; no escutcheon ; ligament external ; muscular scars 

 and hinge-line unknown." 



Observations.— Miller erected this genus for three species of shells from the 

 Hudson River group of North America which had a very ventricose cuneiform shape. 

 Little or nothing is known of the real a linity of the genus, as no details of the interior 

 have been observed. I have quoted the diagnosis of the genus as given by Miller, and 

 I regret that the Scotch examples afford no fresh details. 



Sphenolium richmondense, Miller, 1889. (PI. IV., figs. 30, 31, 31a.) 



Sphenolium richmondense, Miller, 1889, N. Amer. Geol. and Pal., p. 513, figs. 925, 926. 



Specific Characters. — Shell of moderate size, truncate, cuneiform, ventricose, oblique. 

 The anterior end almost obsolete and depressed. The inferior margin bluntly convex ; 

 the posterior rounded below, nearly straight above, oblique, making an obtuse angle 

 with the hinge line, which is arched in front and straight behind. The shell has a very 

 broad oblique gibbosity with a compressed lower and dorsal slope. The umbones are 

 high, incurved, and directed forwards, not contiguous, placed very far forwards. 



Interior. — Unknown. 



Exterior. — Almost smooth, but there appears to have been a thick and wrinkled 

 periostracum. 



Dimensions. — Fig. 30, PI. IV., measures : antero-posteriorly, 31 mm. ; dorso- 

 ventrally, 19 mm. ; gibbosity of valve, 7 mm. 



Localities. — Craighead, Lower Llandeilo ; Woodland Point, Middle Llandovery. 



Observations. — This is a shell that could not easily be mistaken, except perhaps for 

 a Casteropod with an affinity to Capulus. Modiola radiata of the Carboniferous lime- 

 stone has something of the same habit and may belong to the same genus. 



