SPECIES OF CAMERINIDAE BARKER 



315 



OPERCULINOIDES JENNYI, new species 



Plate 12, Figure 7 ; Plate 14, Figuke 7 ; Plate 17, Figure 3 ; Plate 19, Figure 7 ; 



Plate 21, Figure 9 



This species was at first separated into tAvo groups according to the 

 degree of granulation of the sutures and the closeness of the coiling, 

 but it is now believed that only one species is represented with a wide 

 range of variation. 



Test of medium size, compressed lenticular, completely involute, 

 complanate to a variable extent. The sutures are frequently irregu- 

 larly beaded, and the poles are sometimes covered with a thick 

 tuberculate mass of shell material, which is part of the final whorl. 

 The sutures are generally raised, and strongly curved near the periph- 

 ery, which they join at a very oblique angle, as in figures given by 

 Cushman (1921) for O. ocalanus. Diameter, up to 6.0 mm, averaging 

 3.8 mm for 20 specimens ; thickness, 0.8 to 1.0 mm. 



Sections show rather irregular coiling, a very thick outer wall, and 

 a rapidly opening spiral of 2i/^ to 3i/2 whorls, with 18 to 28 chambers 

 in the final whorl. Five sections selected to show the range of varia- 

 tion show the follow^ino- characters: 



The species was at first considered to be a variety of O. ocalanus 

 (Cushman), but careful comparison with material from the Ocala 

 limestone and with figures recently published by Vaughan (1937), 

 taken in conjunction with the discovery of 0. ocalanus at a con- 

 siderably higher horizon in Mexico, have led me to consider this as 

 a distinct new species. Typical specimens of 0. ocalanus show fewer 

 chambers in the final whorl and in general a more rapidly opening 

 spiral, though rare specimens of 0. jennyi occur which show all the 

 essential features of O. ocalanus. 



An interesting character of this species is show^n by transverse 

 sections (see pi. 21, fig. 9). The spiral laminae show incipient sub- 

 division, with splitting off of thin walls, giving lateral cavities sug- 

 gestive of the lateral chambers of the Orbitoididae. This is a sim- 

 ilar character to that shown by Gamerina chaiuneri Palmer, which 



