126 AMERICAN JOURNAL 



the peculiar loop. But little variation was noticed among them, 

 which consisted principally in the greater or less inflation of the 

 valves, and the a])sence or presence of the dental laniinse. 

 Some were slightly more transverse than others, but as 

 a whole they were remarkably uniform. The most transverse 

 individual measured -62 in by -72 long, and '225 diameter. The 

 most compressed measured '50 in. wide by '70 long, and '36 

 diam. A young californica, about the same size, measured -72 

 long by '78 wide, and -55 in. diameter, 



Mr, Davidson suggests that this species may be conspecific 

 with Terehratella ruhpAla, Sby. I have not been able to make a 

 comparison of specimens, but the form of the two species is very 

 similar. The coloration of T. rubella, as figured by Heeve, is 

 very diff'erent, however, as is evident from his comparing it to 

 Wald. 2)icta and from the figures. None of the specimens of 

 suffusus show more than the faintest tinge of salmon color on the 

 stronger lines of growth. 



A comparison of types alone can determine the question. 

 They may or may not belong to the same subsection. 



It is not improbable that after more careful examination of 

 recent species now referred to Terehratella or Waldheimia, others 

 may be referred to this subgenus. 



Subgenus Kingena, Dav. 



Kincjena, Dav., Mon. Cret. Brach. p. 42, 1852. 

 Ismenia, (part). Gray, B. M. Cat. p. 104 (^Megerlia). 

 3Iegerlea, Dav., Mem. Lin. Soc. de Normandie, 1856, p. 263. 

 Terebratula, Auct. 



Shell as in Terehratella, Avith the posterior part of the reflected 

 portion of the loop broad, angulated, with the two angles bent 

 down on each side and joined to the septum directly (not to tho 

 hsemal or septal precesses), forming a broad ring, only inter- 

 sected by the septum. Exterior granulated, foramen entire. 



Tt/jjc. Kingena lima, Defr. sp., Chenu Man. de Concbyl. ii, 

 p. 205, fig. 1052 (as 31. truncata'). PL 8, f. 14. 



Terehratula lima, Defr., Diet. Sci. Nat. 1828, vol. 53, p. 156. 

 Kingena lima, Dav. Mon. Cret. Brach. p. 42, pi. 4, fig. 15 



to 28, pi. 5, fig. 1 to 4. Woodw. Man. p. 219, fig. 103. 

 = Terehratula pentangulata, Woodw., + ventro-plana, Roem., 



+ Hehertiana, D'Orb., + Spinulosa, Morris, -{-sex-radi- 



ata, J. Sby. 

 Fossil in the cretaceous strata of England and France. 

 This subgenus is sufliciently distinct, ancj forms a natural link 

 between Laqueus and Ismenia. 



