FAMILY 45. ORBITOIDIDAE 355 



face papillate. Embryonic chambers bilocular, one somewhat 

 larger than the other, separated by a straight or slightly curved 

 wall, the smaller chamber may be deformed to the contour of the 

 larger, walls pierced by minute cribriform perforations. Equa- 

 torial chambers of two kinds: (a) A spiral of a single row of 

 larger chambers which extend through a little more than a com- 

 plete whorl. The walls of these chambers slope in a curve from 

 their anterior inner ends backward to their posterior outer 

 ends. Outside this row there is a row of smaller spiral cham- 

 bers, (b) Smaller chambers which occupy most of the equa- 

 torial plane. In larger specimens the grov^h may become cycli- 

 cal. The arrangement of the chambers is somewhat irregular 

 with a tendency toward occurrence along radial lines. The 

 outer wall curved ; in the proximal corners of the chambers 

 openings for communication with adjacent chambers, similar to 

 those in Lepidocyclina. In addition to these larger openings, 

 there appear to be minute cribriform perforations. Roofs crib- 

 riform perforate. Lateral chambers irregular but well devel- 

 oped, floor and roofs with cribriform perforations, communica- 

 tions also by passages for protoplasmic stolons. Pillars present. 

 Upper Eocene of the Caribbean region and Peru. 



Subfamily Omphalocyclinae 



Genus OMPHALOCYCLUS Bronn, 1852 



Plate 56, figures 4-6; plate 59, figures 15, 16 

 Genoholotype, Orbidites macroporus Lamarck, 1816 

 Omphalocyclus Bronn, Lethaea geognost., ed. 3, vol. 2, 1851-52, p. 95. 

 Omphahcijcluf! H. DouviLLE, Soc. Geol. France, 4th ser., vol. 20, 1921, 



p. 228, pi. 8, figs. 5-14, text figs. 35-37. 

 Spuradotrcma Hofker, Naturhist. Maanbl. Limburg, Jahrg. 15, 1926, p. 

 62, pL on p. 64, 19 figs, (not Hickson, 1911). 



Test biconcave lenticular. Embryonic chambers quadrilocu- 

 lar. In the central part of the test there is a single layer of 

 chambersS which as growth progresses becomes double, or a 



1 An enlarged photograph of a specimen from 50 mi. n. e. of Sibi, 

 Baluchistan, before me as I write this note, shows two layers of chambers 

 immediately adjacent to the embryonic chambers on each side of them. The 

 two layers extend for seven chambers from the embryonic chambers, and 

 from there outward there is an intermediate layer of chambers. 



