156 T. Davidson — On Tertiary Brachiopoda. 



This species (?) has been well described by the two palaeonto- 

 logists above named. It seems, however, to differ very little from 

 Terebratulina striatula. A single specimen was found by M. 

 Colbeau in the "Laekenien" of Dieghem, near Brussels. It occurs 

 abundantly in the Calcaire Grossier at Parnes, Mouchy, and Chaussy 

 in France. 



9. Terebratulina ornata. Giebel, PI. VII. Fig. 16. 



T. ornata, Giebel, Jahrbuch fur Mineralogie, 1847. T. Nysti, 



Bosquet, Notice sur deux nouveaux Brachiopodes, Acad. 



Eoyale des Sciences, vol. xiv. pi, vi. 1862. 



This species has been described and figured by M. Bosquet from 



a single dorsal valve, found by himself in the lowest bed of the 



Oligocene formation at Hoesfelt, in the Belgian Limbourg ; but he 



informs me by a letter, dated the 26th of April, 1863, that a short 



time after his publication he was able to obtain two examples of the 



Terehratulina ornata of Giebel, the one from Latdorf, the other from 



Westergeln, and that it was then only that he recognized that his 



T. Nysti was the same species. 



10. Argiope Lefevrei, Nyst, PI. VIII. Fig. 8. 



Described by M. Nyst in M. Th. Lefevre and G. Vincent's 



paper on the Upper Laekenien fauna of the neighbourhood 



of Brussels, p. 20, pi. iii. figs. 7, 8. 1873. 



Of this small species a single dorsal valve has been found by M. 



Lefevre in the Lower Zone of the Upper Laekenien formation 



( = Boulder-Clay) of Laeken, in Belgium. It belongs to the division 



Cistella, Gray, and which was created for the reception of those 



species with a single median submarginal septum and bilobed 



loop. 



11. Mawnia Nysti, Dewalque, PL VII. Figs. 10 to 13. 



Dewalque, Prodrome d'une Description Geologique de la 

 Belgique, p. 432. 1868. 



Shell small, triangular, longer than wide, broadly rounded ante- 

 riorly, tapering to an acute termination posteriorly. Dorsal valve 

 moderately convex, ventral valve slightly deeper than the opposite 

 one, without sinus or fold. Beak produced, nearly straight, or very 

 slightly incurved at its extremity, and a little less than a fifth of the 

 length of the shell. Fissure triangular, large and margined laterally 

 by two narrow deltidial plates, commencing under the angular ex- 

 tremity of the beak. External surface of both valves marked by 

 concentric scaly lines of growth, from which scattered adpressed 

 spinules seem to rise. Shell-structure fibrous, no perforations or 

 canals being observable. Length two lines, by one and a half in 

 breadth, and half a line in depth. Owing to the smallness and 

 brittle condition of the shell, it has not been hitherto possible to 

 obtain a perfect interior of the dorsal valve. We cannot, therefore, 

 give of it a complete diagnosis, but will describe and illustrate what 

 we know of it. 



In the interior of the dorsal valve a small cardinal process occupies 

 the centre of the hinge-plate. Prom the inner portion of this plate 

 extend two slender longish lamellae (Fig. II); but as their anterior 



