7 J JURASSIC BIVALVIA AND GASTROPODA 



Liostrea polymorpha (Miinster) 

 PL 9, figs. 3, ya, b 



1833 

 1835 

 1843 

 1857 

 1878 

 1881 

 1917 

 1931 



Gryphaea polymorpha Miinster, in Goldfuss : 31, pi. 86, figs, la, b. 



" Unbestimmt "; Roemer, pi. 3, fig. 12. 



Ostrea romeri Quenstedt : 434. 



Ostrea romeri Quenstedt ; Quenstedt : 625, pi. 77, figs. 22, 23 (?). 



Ostrea roemeri Quenstedt ; de Loriol : 165, pi. 23, fig. 4. 



Ostrea roemeri Quenstedt ; de Loriol : 96, pi. 13, fig. 7. 



Ostrea polymorpha (Miinster) ; Rollier : 592. 



Gryphaea roemeri (Quenstedt) ; Pchelintsev : 67. 



Material. Three specimens, including nos. LL. 35 102-03, a U ex B.P. Coll. 



Locality and horizon. Lihimaliao creek, Mandawa area, Tanganyika ; Upper 

 Oxfordian. 



Remarks. Ostrea roemeri is included in the synonymy of Gryphaea polymorpha 

 on the authority of Rollier and Pchelintsev. G. polymorpha has been misinterpreted 

 by a number of authors as the Lower Bajocian species which has been well figured by 

 Benecke (1905 : 162, pi. n, figs. 1-3) under its correct name Gryphaea ferruginea 

 (Terquem). Both forms lie on the border-line between Liostrea and Gryphaea, the 

 right valve being almost flat and the left valve feebly convex. 



The specimens now recorded are subquadrate to suborbicular in outline and the 

 largest was originally about 70 mm. high. Their general shape is, therefore, rather 

 similar to that of the shell figured by de Loriol in 1881 as Ostrea roemeri. They are 

 broader than Roemer's figure upon which this latter species was founded and Quen- 

 stedt's fig. 22, but in the upper valve of the better preserved specimen (fig. yb) the 

 beak is directed posteriorly in much the same manner as in the figures of these 

 authors. This specimen has a relatively large attachment area whereas that of the 

 specimens figured by previous authors is small. 



The type specimen of L. polymorpha came from the Upper Jurassic (probably 

 Lower Kimmeridgian) of Streitberg, in Franconia. Of the oysters from Cutch, India, 

 described by the present writer (Cox 1952), "Gryphaea sp. indet." (pi. 9, figs, ^a-c) 

 from the Upper Oxfordian seems very close to the specimens now described and 

 could belong to L. polymorpha. 



Subgenus CATINULA Rollier 191 1 



Liostrea (Catinula) alimena (d'Orbigny) 

 PL 9, figs. 6a, b 



18406. Exogyra conica J. de C. Sowerby, pi. 22, fig. 27 (non J. Sowerby sp.). 



1850. Ostrea alimena d'Orbigny : 343. 



19346. Ostrea (" Catinula ") alimena d'Orbigny ; Arkell : 34, pi. 5, figs. 1-15. 



1952. Liostrea (Catinula) alimena (d'Orbigny) ; Cox : 76, pi. 6, figs. 7-10. 



i960. Ostrea (Catinula) cf. ancliffensis Cox & Arkell ; Joubert, pi. 8, fig. 8. 



Material. Several specimens. 



Localities and horizons. 3^ miles W. of Melka Biini, also 11 miles W. of 



