88 Mr. E. B. Newton on 



radiating from the umLonal area wliicli are so cliaractevistic 

 of tlie internal surface-structure of Luciniform shells. 



Dimensions. Umbono-ventral, largest 52 mm., medium 46; 

 anteio-posterior, largest 59, medium 47 ; diameter, largest 23, 

 medium 20. 



Lacs. Kalfu-Taraaskie and Garadimi (fig. 9). 



Golleciors. Colonel Elliot and Captain Lelean. 



Lucina sp. indet. 



Specimen consisting of a natural cast of a Luciniform shell 

 with closed valves possessing nearly central umbones and 

 exhibiting rather wide concentric sulcations. There arc also 

 obscure indications of an angulated posterior area. It is of 

 oval shape, somewhat resembling Fimbria lamdlosa ; but as 

 that species has a more complicated sculpture, and is, more- 

 over, without an angulated area, it need not be confused with 

 the present specimen. 



Dimensions. Umbono-veutrul 40 mm. ; antcro-posterior 

 58 ; diameter 26. 



Lac. Kalfu-Tamaskie. 



Collector. Colonel Elliot. 



Panopcea sahariensis, sp. n. (PI. V. fig. 10.) 



Shell of transversely oval shape, of greater length than 

 height, with anterior umbones and straight hinge-line. Valves 

 inflated in the umbonal region, depressed posteriorly, and 

 with nearly parallel dorsal and ventral margins. Sculpture 

 consisting of rounded, equidistant costae, separated by fairly 

 wide and shallow grooves. 



Dimensions. Umbono-ventral 26 mm. ; antero-posterior 

 (a|)proximate) 50 mm, ; diameter 27. 



Shell related to Mya intermedia of James Sowerby, oc- 

 curring in the Eocene deposits of Britain and Europe, but 

 appearing to differ chiefly in its lesser umbono-ventral 

 measurement^ and the possession of nearly parallel dorsal and 

 ventral margins. The sculpture is very similar, the broad 

 equidistant sulcations being clearly expressed. The dorso- 

 posterior part of the valve shows an oblique dcjiression 

 extending from the umbonal region to the outer margin, 

 whilst a second specimen proves that the anterior region was 

 very short. 



Two fragmentary natural casts with closed valves repre- 

 sent this form ; that figured and described is imperfect 

 anteriorly. 



Loc. Kalfu-Tamaskie. 

 Collector. Colonel Elliot. 



