ORDOViCIAN AND SILURIAN BRACHIOPODA OF THE GIRVAN DISTRICT. 809 



shell from Craighead in Mrs Gray's collection which has the radial lines of tubercles 

 rather more closely placed and the tubercles themselves more prominent than in 

 the Balclatchie form, but it can scarcely be separated. 



This shell is much like our L. pulcherrimum, and is undoubtedly allied to it, but 

 the ornamentation is coarser. 



Ulrich # has suggested that Billings' Lingula canadensis t may belong to the 

 genus Lingulasma, but unfortunately the type of Billings' species is lost, and 

 apparently no other specimens are known.! Lingulasma Schucherti, Ulrich (op. cit.), 

 from the " Hudson River Group," § is the type of the genus. 



Horizons. — (l) Balclatchie Group ; (2) Stinchar Limestone Group. 



Localities. — (l) Balclatchie ; (2) Craighead. 



Lingulasma ? penultimum, sp. nov. 

 (Plate II, figs. 25, 26.) 



Shell regularly oval, biconvex, widest across middle, sides arched ; anterior end 

 rounded or slightly subtruncate. Brachial valve rather flatter than pedicle-valve. 

 Shell thick, laminated, longitudinally striated over whole interior. Surface of shell 

 covered densely with small equal rounded granules arranged in regular concentric 

 and radial rows ; granules closely placed, equidistant, less than their own diameter 

 apart. 



Dimensions. — Length about 15 mm. ; width about 10 mm. 



Horizon. — Drummuck Group (Starfish Bed). 



Locality. — Thraive Glen. 



Remarks. — Only one specimen of this species is known to me, but it is nearly 

 perfect, with the exception of the beak of the pedicle-valve. The ornamentation is 

 much like that of the other species here referred to IAngulasma, and especially to 

 L. granulata, Phillips, || which Ulrich H suspected belonged to this genus. Un- 

 fortunately, the internal characters of this Girvan shell are unknown. In L. granulata 

 the shell is quadrate in form and the granules are coarser. In L. tenuigranulata, 

 M"Coy,* # the radial arrangement predominates and the shell is of a different shape. 



Lingulasma ? pulcherrimum, sp. nov. 



(Plate II, figs. 27, 28 ; Plate III, fig. 1.) 



Shell elongated oval to sub-oblong, nearly twice as long as wide ; sides gently 

 arched, subparallel ; anterior end rather abruptly rounded. Pedicle-valve with 



* Ulrich, American Geologist, vol. iii, No. 6, 1889, p. 383, figs, ha, b, c, d (p. 378). 



+ Billings, Palseoz. Fobs. Canada, vol. i, 1862, p. 114, fig. 95 ; Winchell and Schuchert, Palseont. Minnesota, 

 iii, p. 352, fig. 26. 



X Hall and Clarke, Palseont. New York, vol. viii, 1892, Brach., i, p. 27. 



§ Hall and Clarke, ibid., pi. ii, figs. 17-23. 



|j Davidson, Mon. Brit. Foss. Brach., vol. iii, pt. vii, p. 36, pi. ii, figs. 15-18. 



1 Ulrich, Amer. Geol., iii, 1889, p. 389. ** Davidson, op. cit., p. 37, pi. ii, figs. 9-14 



