114 AMERICAN JOURNAL 



Schloth., Dav. An. of Nat. Hist. 1850, pi. xv, figs. 5, a, b. The 

 structure of Stringocephalus, while sufficiently distinct to de- 

 serve a section to itself, is most nearly allied to that of the sep- 

 tate Waldheimias, near ^vhich I hnve placed it. 



Stringoceplialus, according to JNIr. Davidson, has only been 

 found in strata of the Devonian age. 



Messrs. White and St. John have provisionally indicated a 

 new form under the name of Cri/ptaeanthia, (Trans. Chicago 

 Acad, Sci., i. p. 119, 1868,) which presents some analogies with 

 String ocephahis, Waldheimia and Terehratulina. "The loop 

 seems to be essentially like that of Waldheimia in form, but the 

 crura of the loop appear to be joined, * * * ^^d the loop- 

 band is armed with numerous spines Avhich point outward toward 

 the shell (?) in all directions," W. and St. J. loc. cit. It can- 

 not be determined from this description whether the spines are 

 directed toward the margin or the body of one of the valves,. but 

 it affords another argument against affiliating Stringocephalus 

 with JlegatJigris from the mere presence of such appendages. 



Type Waldheimia? compacta, W. and St. J. Tr. Chic. Acad. 

 Sci. I., p. 119, fig. 3, a, b, c. 



Section MAGASIN.^. 



Blagasina, Gray, B. M. Cat., p. 85, 1853. 



Loop reflected, attached both to the hinge margin and to the 

 septum of the hjemal valve. 



Genus TEREBRATELLA. 



Apophyses with their lia3mal arms connected with the septum 

 by two (septal) processes. 



Subgenus Trigonosemus. 



Trigonosemus, Konig, Icon. Sect. 1825, p. 3, f. 73. (T. ele 



gans). 

 Fissurirostra, D'Orbigny, Pal. Fran. Cret. p. 133, fig. 5*20. 



(F. recurva), 1847. 

 Fissirostra, D'Orb., Cours. El. Pal., p. 89, 1849. 



Shell with produced curved beak or umbo in the neural valve ; 

 a minute apical foramen ; a large triangular area, flat and 

 marked by the outline of the flat deltidium ; cardinal process 

 very prominent. Loop as in Terehratella. 



Type Trigo7iosemus elegans. Konig. Fossil in the Cret. 



I can only concur with Mr. Davidson in considering this sec 



