954 DR F. R. C. REED ON THE 



Dimensions. — Length, 18*5 mm. ; width, 17*5 mm. ; thickness, 10*0 mm. 

 Horizon. — Mulloch Hill Group. 

 Locality. — Mulloch Hill. 



Whitfieldella 1 sp. 

 (Plate XXIV, fig. 52.) 



One internal cast of a brachial valve of a simple subcircular moderately convex 

 shape is doubtfully referred to the genus Whitfieldella. There is no median fold, and 

 the surface is uniformly convex. The hinge-plate is very large and stout, triangular 

 in shape, thickened anteriorly, and fills the whole umbonal region and is cleft clown 

 the middle by a narrow slit. The anterior edges of these halves into which it is 

 divided are furnished with short sharply pointed thin laminar crura curved inwards. 

 There is a weak low rounded ridge between the narrow elongated parallel muscle- 

 scars which extend more than half (?) the length of the shell. The hinge-plate and 

 crura seem to resemble those of Hyattidina [=Hyattella, Hall and Clarke, non For] 

 rather than Wliitfieldella or any other genus, but it is possible that the genus 

 Hindella, of which the internal characters of the brachial valve are incompletely 

 known,* should receive it. 



Dimensions. — Length about 10'5 mm. ; width about 11 '5 mm. 



Horizon. — Drummuck Group (Starfish Bed). 



Locality. — Thraive Glen. 



Genus Meristella, Hall. 



Meristella cf. Circe, Barrande. 



(Plate XXIV, figs. 53, 54.) 



Cf. 1847. Terebratula Circe, Barrande, "Silur. Brach. Boheme," Nat. Abhandl. vol. i, p. 37, pi. xvi, 

 fig. 6. 



Shell oval to elongated subpentagonal ; margin sinuated. Pedicle-valve convex, 

 with broad shallow sinus arisina; at about half to two-thirds the length of the valve 

 and produced anteriorly into short rounded tongue ; edges of sinus formed by low 

 narrow folds, slightly divergent or subparallel ; narrow rounded median fold in sinus, 

 weakly developed near beak but becoming stronger anteriorly ; interior of valve with 

 pair of thin dental plates converging at first inwards and then running forwards 

 nearly parallel for less than half the length of valve and enclosing between them a 

 small low boss or thickening of the shell at their point of convergence, with narrow 

 ridged diductor scars in front of it. Surface of shell marked with a few strong 

 concentric growth-ridges and striae. Brachial valve unknown. 



Dimensions. — Length, 9"0 mm. ; width, 7'5 mm. 



Horizon. — Mulloch Hill Group. 



* Hall and Clarke, op. cit, Brach., ii, p. 65, 



