FORAMINIFERA OF NORTH PACIFIC OCEAN. 77 



The groups of species which have numerous chambers in each coil 

 and a definite umbilicus, with other accompanying characteristics, are 

 grouped under the new genus Buliminella, and the single species 

 Bulimina wiUiamsonii IT. B. Brady, which has the chambers hidden 

 at the surface by the ornamentation, but nevertheless spiral, and the 

 a | torture central and terminal, has been made the type of the new 

 genus Buli nt inoides. 



There is a considerable range of species characters in the species 

 of Bulimina as restricted, the chambers in certain forms becoming 

 rapidly larger, and in the adult hiding the earlier or becoming larger 

 with an accompanying extension of the axis of the spire forming a 

 long tapering test with the triserial arrangement visible throughout. 



From the difficulty of examining the proloculum and early cham- 

 bers, little is known concerning the occurrence of the microspheric 

 and megalospheric forms in the species of this genus. 



BULIMINA OVATA d'Orbigny. 



Bulimina ovata d'Orbigny, For. Foss. Vienne, 1846, p. 185, pi. n, figs. 13, 

 14.— H. B. Brady, Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 400, pi. 50, 

 figs. 13a, b. 



Description. — Test ovate in front view, circular or nearly so in end 

 view, the apex broadly rounded; visible chambers several, little 



l'n,. L25. — Bulimina ovata. X -iO. a, front view; b, end view: c, view showing aperture. 



inflated; sutures but slightly compressed; wall smooth; aperture 

 rather narrow with a plate-like tooth; color white. 



Length 0.75-1.20 mm. 



Distribution. — Rather common throughout the area, except in very 

 deep water. 



The smooth species of Bulimina are in an extremely confused state, 

 and as the material I have examined is insufficient to determine defi- 

 nitely the interrelationships of all the forms, they are referred to cer- 

 tain general species, usually taking the figures given by Brady as a 

 broad basis for distinguishing the forms. 



Brady's figure of Bulimina ovata is referred by does to B. ellip- 

 soides Costa. 



