62 Jl'RASSIC BIVALVIA AND GASTROPODA 



Remarks. This species closely resembles Lima (PI agio stoma) punctata J. Sowerby, 

 of the Lias. Of comparable Upper Jurassic species, L. boidini Sauvage (de Loriol 

 1875 : 171, pi. 21, figs. 8, 9), Portlandian of northern France, is elongated in a more 

 oblique direction and its punctate grooves are more broadly spaced. L. libanensis 

 Krumbeck (1905 : 99, pi. 10, fig. 5), Lower Kimmeridgian of Syria, is described as 

 having distinctly raised but at the same time very depressed ribs, although this is not 

 obvious in the figures. L. harronis Dacque (1905 : 133, pi. 15, figs. 13, 14), Kim- 

 meridgian of Somaliland, is a narrower and more oblique shell with distinctly raised 

 ribs. L. thisbe de Loriol (1888 : 322, pi. 36, figs. 1-4), Lower Kimmeridgian of the 

 French Jura, and L. burensis de Loriol (1893 : 331, pi. 34, figs, n, 12 ; 1895 : 47, 

 pi. 9, fig. 2) and L. trembiazensis de Loriol (1901 : 102, pi. 5, fig. 24), both from the 

 Upper Oxfordian of the Swiss Jura, have distinctly raised ribs separated by punctate 

 grooves which are more closely spaced than in the form now described. 



Lima {Plagiostoma) sublaeviuscula Krumbeck 

 PL 8, figs. 5, 6 



1905. Lima sublaeviuscula Krumbeck : 99, pi. 3, figs. 3a, b. 



Material. Two specimens. 



Locality and horizon. 5 miles S. of Galgali Gambo, N.E. Kenya ; Upper 

 Kimmeridgian, Dakacha Limestones. 



Remarks. These specimens, the larger of which is about 80 mm. high, are larger 

 than Krumbeck's type-specimen, but are similar to it in shape and have exactly the 

 same characteristic ornament of very depressed radial ribs which are unequal and 

 irregularly spaced, and are confined to the anterior, posterior and ventral parts of 

 the surface, the middle of which is smooth. The intervals between the ribs are 

 relatively narrow and do not seem to be punctate. It seems doubtful if L. informis 

 Krumbeck (1905 : 100, pi. 3, figs, ya-c) is specifically distinct from L. sublaeviuscula, 

 although stated to be less inequilateral, higher in proportion to its breadth and more 

 gibbose, and to have a shorter and broader lunule. Both forms, described originally 

 from the Lower Kimmeridgian of Syria, differ only in minor details from the Upper 

 Oxfordian species L. laeviuscula (J. Sowerby), in which the shell seems to be slightly 

 broader and the ribs less numerous. A specimen (L. 92235) from the Seir Limestones 

 (Oxfordian) of N. Kenya identified (Joubert i960, pi. 8, fig. 6) as Lima (Plagiostoma) 

 cf. laeviuscula may well belong to Sowerby's species, but is broken anteriorly and too 

 imperfect for definite identification. 



Subgenus ACESTA Adams 1858 



Lima (Acesta) kindopeensis sp. now 



PI. 8, fig. 10 



Diagnosis. Of medium size (height of holotype c. 47 mm.), ovate-trapezoidal, 

 with a slight lunate tendency ; length, parallel to hinge-margin, almost equal to 



