36o CRETACEOUS PALEONTOLOGY. 



1829. Terehratula fragilis Mort., Am. Jour. Sci., ist ser., vol. 



17, p. 283; vol. 18, p. 250, pi. 3, fig. 17. 

 1834. Terehratula fragilis Mort., Synop. Org. Rem. Cret. Gr. 



U. S., p. 70, pi. 3, fig. 2. 

 1886. Terehratula Harlani var. fragilis Whitf., Pal. N. J., vol. 



I, (Monog. U. S. G. S., vol. 9), p. 7, pi. i, figs. 15-18. 



Description. — The name fragilis was applied by Morton to 

 those specimens of T. harlani which are more conspicuously pli- 

 cated anteriorly than usual. There is no sharp line of demar- 

 cation between the variety and the more typical form of the 

 species, all intermediate variations being met with, and all of 

 them occurring together. It will, perhaps, be a matter of con- 

 venience tO' reco'gnize this form under a varietal name, and if this 

 is done, Morton's name fragilis takes precedence, although it has 

 no- especial significance, the shells being no more fragile than 

 those of the typical T. harlani. 



Genus TerEbraTulina d'Orbigny. 



Terebratulina atlantica (Morton). 



Plate XXVIII., Figs. 9-12. 



1842. Terehratula atlantica Mort., Jour. Acad. Nat. Sci. Phil., 



1st ser., vol. 8, p. 214. 

 1861. Terehratulina Halliana Gabb, Proc. Acad. Nat. Sci. 



Phil, 1861, p. 19. 

 1861. Terehratulina Halliana Gabb, Synop. Moll. Cret. Form., 



p. 256 (200). 

 1864. Terebratulinci Halliana Meek, Check List Inv. Foss N. 



A., Cret. and Jur., p. 5. 

 1868. Terehratula glossa Con., Cook's Geol. N. J., p. 377, 



figure; p. 723. 



1868. Terehratulina Hailimia Con., Cook's Geol. N. J., p. 724. 



1869. Terehratula glossa Con., Am. Jour. Conch., vol. 5, p. 42, 



pi. I, fig. 22. 

 1886. Terehratulina Atlantica Whitf., Pal. N. J., vol. i 



(Monog. U. S. G. S'., vol. 9), p. 9, pi. i, figs. 10-13. 

 1892. Terehratulina atlantica Hollick, Trans. N. Y. Acad. Sci., 



vol. II, p. 98, pi. I, fig. 8. 



