FROM TANGANYIKA AND KENYA 61 



Locality and horizon. Muddo Erri, N.E. Kenya ; Callovian [?-Lower Oxford- 

 ian], Muddo Erri Limestones. 



Remarks. This Lima, although rather similar to several previously described 

 species, cannot be identified definitely with any of them. L. complanata Laube 

 (1867 : 24, pi. 1, fig. 11), Callovian of Poland, has a narrower body and umbonal 

 region, a smaller posterior auricle, and more ribs. In L. paolii Stefanini (1939 : 164, 

 pi. 19, figs. 7, 8), from the " Lower Oolitic " of Somaliland, there are 36-38 ribs 

 which are much more depressed than in the new species and have narrower intervals. 

 In L. subcardiiformis Greppin, a widespread Bathonian species, the ribs are much 

 more numerous. Of the varied series of Limidae occurring in the Bajocian of England, 

 L. bradfordensis Cox (1943 : 159, pi. 9, fig. 10) is quite closely similar to the present 

 species, but its ribs are relatively broader and their intervals narrower. L. notata 

 Goldfuss (1836 : 83, pi. 102, figs. la, b), of the Upper Oxfordian and Kimmeridgian, 

 is more equilateral in outline. 



Lima (Plagiostoma) cf. jumaraensis Cox 



1952. Cf. Lima {Plagiostoma) jumaraensis Cox : 52, pi. 5, figs. 4a, b, 5. 



Material. About four ill-preserved specimens. 



Locality and horizon. Kulong, 2 miles S.W. of Muddo Erri, N.E. Kenya ; 

 Callovian [?-Lower Oxfordian], Muddo Erri Limestones. 



Remarks. In this species, originally described from the Bathonian and Callovian 

 of India, the narrow ribs are very depressed, projecting only slightly between the 

 radiating linear grooves which separate them. In the specimens now recorded the 

 ornament agrees well with that of the Indian ones, but not one is well enough pre- 

 served to show the complete outline of the shell. The specimens from Somaliland 

 recorded by Stefanini (1939 : 162, pi. 19, figs. 5a, b, 6a, b) as Lima [Plagiostoma) 

 strigillata Laube are very similar to those now described, some of which were pro- 

 visionally identified (Joubert i960 : 18) as Laube's species after comparison with 

 Stefanini's figures. 



Lima {Plagiostoma) rahmuensis sp. nov. 

 PI. 7, figs, iofl, b 



Diagnosis. Of medium size (height of holotype c. 35 mm.), trapezoidal, slightly 

 higher than long, well inflated. Ventral margin moderately asymmetrical ; um- 

 bonal region obtusely angular in outline, its angle about 120° ; anterior umbonal 

 ridge rounded off, straight, not greatly elongated, forming an angle of about 45 ° 

 with the hinge-margin ; lunule well excavated. Main part of surface bearing 

 numerous punctate linear radial grooves, about 7 of which occcupy a width of 5 mm. 

 near the ventral margin ; spaces between grooves quite flat. 



Holotype. No. L. 83892. The only specimen. 



Locality and horizon. z\ miles S.W. of Rahmu, N.E. Kenya ; Oxfordian, 

 Rahmu Shales. 



