12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I42 



22 mm. in width, and 15 mm. in height. These dimensions fall within 

 the range in size of the typical form, of which a large series is 

 available. 



Specimens from Cuba at first identified by Lambert as Oligopygns 

 wetherbyi de Loriol and figured under that name by Sanchez Roig 

 (1926, p. 82, pi. 13, figs. lo-ii) were later renamed Oligopygus cuben- 

 sis Lambert (1931, Soc. Geol. France Bull., ser. 5, vol. i, p. 292). This 

 name appears to be a synonym of typical Oligopygus haldemani 

 (Conrad). 



The most conspicuous difference between Oligopygus wetherbyi, 

 the type species of Oligopygus, and O. haldemani is the location of 

 the periproct. In O. wetherbyi it lies midway between the margin 

 and the peristomial depression, in O. haldemani closer to the margin. 

 O. haldemani is usually the smaller. 



Occurrence. — Trinidad: Bella Vista quarry (Mene Grande Oil Co. 

 19059). 



Geologic horison. —Lsite Eocene : San Fernando formation. 



Holotype. — Naturhistorisches Museum, Basel, Switzerland. 



Figured specimen. — USNM 638626, a topotype. 



OLIGOPYGUS ROTUNDUS Cooke 

 PI. 3, figs. 4-6 



lOligopygus christi Jeannet, 1928, Soc. Paleont. Suisse Mem., vol. 48, p. 10, 



pi. I, fig. 19; pi. 6, fig. 2. Not pi. I, figs. 16-18. 

 Oligopygus rotundus Cooke, 1942, Journ. Paleont., vol. 16, No. i, p. 9, pi. 2, 



figs. 1-3. 

 Oligopygus rotundus Cooke. Cooke, 1959, U. S. Geol. Surv. Prof. Pap. 321, 



p. 29, pi. 8, figs. 1-5. 



Horizontal outline nearly circular ; upper surface inflated ; lower 

 surface flatter ; margin broadly rounded. Apical system central, tumid, 

 monobasal ; four genital pores. Petals tumid ; paired petals extending 

 more than halfway to the margin, odd petal somewhat longer ; porifer- 

 ous zones narrow, regularly expanding, open distally; pores circular, 

 conjugate. Peristome central, oval, at the bottom of a deep, straight- 

 walled transverse depression occupying less than one-third of the total 

 diameter of the test. Periproct small, round, flush, near the posterior 

 third of the lower side. Tubercles rather large, sunken ; intermediate 

 spaces granulated. 



Length of holotype 22 mm.; width 20.7 mm.; height 11.2 mm. 

 Occurrence. — Alabama: Koons Mill on Cripple Creek, Geneva 

 County (holotype). 



