818 DR F. R. C. REED ON THE 



Genus Trematis, Sharpe. 



Trematis craigensis, sp. nov. 



(Plate IV, figs. 6-9.) 



Shell obovate to subcircular, widening slightly anteriorly. Brachial valve gently 

 convex ; beak blunt, intramarginal, not projecting ; interior with median muscle-scar 

 formed by pair of elongated subtriangular " central " muscles situated behind centre 

 of valve, separated by very low weak median septum ; marginal scars indistinct. In- 

 ternal surface of shell marked by very fine radial striae ; external surface covered 

 with small closely placed hexagonal cells separated by narrow walls ; cells becoming 

 smaller near margins. Pedicle-valve unknown. 



Dimensions. — Length, 13 mm. 



Horizon. — Stinchar Limestone Group. 



Locality. — Craighead. 



Remarks. — This species is undoubtedly allied to T. punctata (Sow.)* and T. 

 millepunctata, Hall,t but the shape of the shell is rather different and the external 

 ornament is finer, the cells being smaller than in the former species, and the beak of 

 the brachial valve in the latter is more prominent and the central muscle-scars more 

 anteriorly placed, being almost in the middle of the shell. 



Trematis melliflua, sp. nov. 

 (Plate IV, fig. 10.) 



Shell transversely subcircular ; brachial valve gently convex [? with weak median 

 depression from beak to margin] ; beak marginal, blunt, slightly incurved ; surface 

 of shell marked with a few concentric growth-ridges and covered with very minute 

 closely placed hexagonal pits, arranged in quincunx manner ; no radiating lines 

 present. 



Dimensions. — Length, 5'1 mm. ; width, 6*3 mm. 



Horizon. — Balclatchie Group. 



Locality. — Balclatchie. 



Remarks. — The absence of radiating lines and the densely placed very small pits 

 give a minutely cancellated or honeycomb appearance to the shell-surface, as in 

 Trematis millepunctata, Hall,| from the Hudson River [Lorraine] Group, with which 

 species ours may be compared. I am only acquainted with one specimen of this 

 interesting little brachiopod, and it is in Mrs Gray's collection. The median 

 depression may be due to crushing and thus not be an original or specific feature. 

 The shape of the shell and the much finer ornament distinguish this species from 

 that of the Stinchar Limestone termed T. craigensis. 



* Davidson, Mon. Brit. Foss. Brack., vol. iii, pt. vii, p. 69, pi. vi, fig. 9. 

 t Hall, 24th Ann. Rep. N.Y. State Gab. Nat. Hist., 1872, p. 221, pi. 7, figs. 22-25. 



{ Hall and Clarke, Palneont. New York, vol. viii, Brack., i, p. 139, pi. ivc, figs. 4-10 ; Schuchert, Bull. 87, 

 U.S. Geol. Surv., p. 452 (for references). 



