203 



This shell differs from the type in the more obtuse and tumid nmbo 

 of the dorsal valve and the heavier and more prolonged umbo of the ven- 

 tral valve. 



LlNGULELLA, cf. DAVISII, McCoy. 



Examples of a Linguella which though smaller than the above species Lingulella of. 

 of the Lingula flags and Tremadoc slates of Britain, has the same gene- Dav1811 - 

 ral form, are found in the Asaphellus beds of Cape Breton. It has the 

 nearly straight base and sub-parallel sides of McCoy's species. The dor- 

 sal valve has on the interior a median septum two-fifths of its length, 

 and the whole interior, especially towards the umbo, is marked with scat- 

 tered pits. 



Sculpture. Externally this shell has fine concentric ridges, which are 

 crossed by very fine radiating striae. The middle third is marked by 

 numerous, fine, radiating, vascular lines, and the lateral borders are flat- 

 tened at the sides. 



Size. Length, 10J mm. ; width, 9 mm. Infrequent. 



Horizon and locality. In the gray shale of Assise C. 3 c 2 , at McLeod 

 brook, Boisdale, N.S. 



LlNGULELLA CONCINNA, PI. XIV, figs. 5a-6. 



Lingulella concinna, n. sp. Bull. Nat. Hist. Soc. of N. B., vol. iv p. 273 

 pi. v, figs. 2 a and b. 



Occurring in the dark gray shales of the Upper Cambrian on McLeod Lingullela 

 brook are a few examples of a small Lingulella, smoother than the species described, 

 from the same beds referred provisionally to L. lepis, but ornamented, as 

 that species is, by concentric ridges. 



The shell substance is quite thin towards the lateral and front margins, 

 and is there flattened out by pressure. The beak is somewhat blunt, and 

 the rounded lateral margins give the ventral valve an ovate form. 



Sculpture. Over the visceral space the surface of the valves is covered 

 with very fine concentric somewhat lamellose ridges, visible with a lens ; 

 over the branchial area these ridges flatten down, and the valve has a 

 shining granular surface ; the ridges, however, remain distinct on the 

 lateral margins, though there also the surface is bright. 



* Introduction to study of Brachiopoda, Hall & Clarke, p. 229 ; fig. 23, and pi. 2, 

 fig. 5. 



fU. S. Nat. Mus. Proc. vol. XXI, p. 385. PI. xxvi; fig. 1. 



Jimp. Acad. des Sci., St. Petersburg. Ser. VIII, Tom. iv, No. 2. PI. II, figs. 

 19c and 21c. 



