Manchester Memoirs, Vol. Ixii. (19 17 ; 75 



160. Nodosaria semirugosa, d'Orbigny. 



Nodosaria semirugosa, d'Orbigny, 1846, Foram. toss. Vienne, 



p. 34, pi. I, figs. 20-23. (N. rugosa on plate.) 

 N. costulata, Brady, 1884, Chall. Rep., p. 515, p. LXIII, figs. 



More frequent than the last-named species. Besides the 

 typical form with short costse on the base of each segment only, 

 there are to be found specimens in which the costae are longer, 

 and so on by small gradations up to a form in which the surface 

 ornamentation is continuous with the length of the segment. 

 In this case the costs are sometimes few and feebly developed, 

 and sometimes very strong, in the latter specimens the chambers 

 are more elongate than in the type. 



(Halkyard originally named his specimens N. costulata 

 Reuss, and would have been well advised to have adhered to 

 this name. The specimens though fragmentary are much 

 nearer the Pietzpuhl figure of N. stipiiata var. costulata Reuss 

 (S. 1870 F.S.P. pi. VII. fig. 20.) with elongate chambers merg- 

 ing imperceptibly into a thick costulate neck, than to 

 d'Orbigny's earlier species N. semirugosa, in which the cham- 

 bers are nearly globular, and the stolon passages long and 

 delicate.) 



161, Nodosaria (Dentalina) obliquestriata, Reuss. 



Dentalina obliquestriata, Reuss, 1851, Zeitschr. deutsch. geol. 

 Ges- vol. Ill, p. 63, pi. Ill, figs. 11, 12. 



This species occurs both at the top and bottom of the Marl 

 beds, as well as at some intermediate points, but is rather rare 

 and the specimens are small. 



(The specimens are nearly all very small and weak. 

 N. obliqua (Linne.) should except for taxonomical purposes 

 include all these costate forms, the variations of the numerous 

 sub-species resting entirely upon the strength of the costse and 

 their tendency to follow the curve of the shell, or to run trans- 

 versely across the chambers.) 



162. Nodosaria perversa, Schwager. 



Nodosaria perversa, Schwager, 1866, Novara-Exped., Geol. (2), 



p. 212, pi. V, fig. 29. 

 -V. perversa, Brady, 1884. Chall. Rep., p. 512, pi. LXIV, figs. 



25-27. 



