OBOLID^. 557 



Lingula pygmaea Salter, Davidson, 1866, British Fossil Brachiopoda, vol. 3, pt. 7, No. 1, p. 53, PL II, figs. 8 and 8a. 



(Text and figures copied from the preceding reference.) 

 Lingula pygmxa Salter, Phillips, 1871, Geology of Oxford and the Valley of the Thames, p. 68, Diagram XVII, fig. 13. 



(No text reference.) 

 Lingula jtygmxa Salter, Matlet, 1902, Quart. Jour. Geol. Soc. London, vol. 58, p. 141. (Synonymy given and species 



mentioned.) 



The original description by Salter follows: 



Minute, subcylindrical, gibbous; beak somewhat obtuse; anterior margin truncate; shell thin; surface finely 

 striated transversely. Length, j\- inch; width, ^-^ inch. In the Black shales. 



The Black shales are refei'red to the Upper Cambrian, the locality being in the eastern por- 

 tion of the Malvern Hills of England. Davidson [1866, p. 53] states that he could only repro- 

 duce Salter's description and figure, as he had not seen specimens of the shell. The figure given 

 by Salter [1865, figs. 8a and 8b, p. 101] is that of an elongate, cuneate shell more like the typical 

 form of Lingulepis than Lingulella. From its form and the fact that it occurs in association 

 with the Olenus fauna it is probable that it should be referred to Lingulepis. 



Formation and locality. — Upper Cambrian: (304f [Salter, 1865, p. 102]) "Black shales" in the Malvern Hills, 

 between Herefordshire and Worcestershire, England. 



Lingulella (Lingulepis) robeeti (Matthew). 

 Plate XXXVII, figures 4, 4a-d. 



Lingulella roberti Matthew, 1895, Trans. Roy. Soc. Canada for 1895, 2d ser., vol. 1, sec. 4, No. 13, pp. 256-257, PI. I, 

 figs. 2a and 2b. (Described and discussed as a new species. Plate XXXVII, figs. 4, 4a-d of this monograph are 

 drawn from specimens in Matthew's type material, and it is possible that the specimens represented by figs. 4a 

 and 4b are the ones figured by Matthew, figs. 2a and 2b, respectively, but positive identification is impossible.) 



Lingulepis roberti Matthew, 1903, Geol. Survey Canada, Rept. Cambrian Rocks Cape Breton, p. 132, PI. VIII, figs. 

 5a-b. (Text and figures copied from the preceding reference.) 



General form elongate ovate, with the ventral valve acuminate and the dorsal round ovate. 

 The cardinal slopes of the ventral valve are in some shells slightly incurved as in Lingulella 

 {Lingulepis) acuminata (Conrad); a portion of this curvature, as shown in Plate XXXVII, 

 figures 4 and 4a, may be owing to the lateral compression of the shells. The convexity of the 

 ventral valve is moderate, while that of the dorsal is unusually large (PI. XXXVII, fig. 4b). 

 This may be owing to the deformation of the shell by lateral pressure in the matrix. 



Surface of the shell marked by very fine, obscure, radiating striee and narrow undulations, 

 and very fine, irregular, concentric striae between relatively strong striae and lines of growth. 

 The irregular striae inosculate, Plate XXXVII, figure 4c, so as to give an appearance much 

 like that of Oholus (Westonia) ella (Hall and Whitfield) (PL XLVII, fig. lo). When the thin 

 outer layer is exfohated, the dark shiny surface of the inner layers shows radiating striae and 

 concentric lines of growth. The inner surface appears to have been punctate to a moderate 

 degree. The shell is moderately thick and is built up of a thin outer layer and several inner 

 layers or lamellae that anteriorly are sUghtly obUque to the outer layer, much as in Lingulella 

 acutangula (Roemer). 



The largest ventral valve among the type specimens has a length of 13 mm.; width, 9 

 mm.; the width is narrowed 2 or 3 mm. by the lateral compression. A dorsal valve that 

 is very httle, if any, distorted is 10 mm. long and 10 mm. wide. A trace of the pedicle groove 

 in the ventral valve is shown by Plate XXXVII, figure 4a. The area of the dorsal valve is 

 not preserved in any of the specimens sent to me by Matthew. 



The cast of the visceral cavity is shown in Plate XXXVII, the ventral valve in figure 

 4a and the dorsal valve in figure 4b. 



The anterior lateral and central muscle scars are seen in the specimens of the type sent 

 me by Matthew. In g and h, figure 4b, of Matthew's figures, the umbonal scar is short and 

 broad, as in Oholus selwyni (Matthew) (PI. XXXVII, fig. If). 



The marldngs of the vascular system observed are the main vascular sinuses of the ventral 

 valve, a trace of them in the dorsal valve, and a little of the parietal scar about the visceral 

 cavity in the dorsal valve (fig. 4b). 



