538 B. BuUen Newton — Egyptian Loicer Tertian/ Shells. 



Genus AECA, Linngeus. 

 Systema Naturse, 1758, ed. x, p. 693. 

 Type. — A. Noes, Linnasus. 



Aeca Esnaensis, sp. nov. (PI. XIX, Figs. 15, 16.) 

 Description. — Shell small, inequilateral, moderately convex,, 

 transversely oval ; surface ornamented with a close cancellation 

 formed by a series of radial, fimbriate cost^e, crossed by concentric 

 striee, which at the junctions assume a noded or beaded appearance ; 

 valve slightly depressed in the centre ; carination oblique and 

 dorsally acute ; margins more or less rounded ; slight mesial 

 depression present. 

 Dimensions. 



Height 11 mm. 



Length 18 mm. (about). 



Eemakks. — This description is drawn up from a single right 

 valve, embedded in the same matrix as contains Pecten Mayer- 

 Eymari. The specimen has a highly ornamented test, with rays of 

 equal thickness and a uniform distance from each other. One of 

 the margins is round, the other imperfect. It is most closely related 

 to Area appendiculata of J. Sowerby, especially in its decussated 

 sculpture, aud is doubtless a good Eocene form of the genus. From 

 its rarity in Egyptian rocks the specimen is considered of sufficient 

 importance to merit a notice under the present new name. 



Horizon. — Lower Eocene (Libyan Series). 



Distribution. — Egypt : right bank of river Nile opposite Esna, 

 Coll. Geol. Surv. Egypt (No. 1,003, Box No. 49* c). 



Genus MACROSOLEN, Mayer-Eymar. 



PalaeontograpMca, vol. xxx (1883), p. 116. 

 Type. — Sangiiinolaria Hollowaysi, J. Sowerby. 

 Macrosolen Hollowaysi, J. Sowerby. (PI. XX, Figs. 7, 8.) 

 Sanguinolaria EoUowaysi, J. Sowerby : Mineral Conchology, vol. ii 



(1817), p. 133, pi. clix. 

 Solen uniradiatus, Bellardi, " Cat. Foss. Numm. Egitto " : Mem. E. Ac. 



Sci. Torino, ser. ii, vol. xv (1854), p. 16, pi. ii, fig. 5. 

 Sanguinolaria [Macrosolen) Holloioaysi, Mayer-Eymar in Zittel : 



Palaeontographica, vol. xxx (1883), p. cxvi. 

 Gari (?) Hollowaysi, E. B. Newton : Syst. List Edwards Coll. 

 Brit. Mus., 1891, p. 76. 

 Description. — This species was originally described as "depressed, 

 transversely elongate, ovate, and striated ; anterior [should be 

 posterior] side gradually expanded; posterior [should be anterior] 

 side very small." 



It is a well-marked shell, and easily distinguished by its trans- 

 versely elongate shape, the very anterior position of the umbones, 

 and the oblique furrow extending from the umbonal area to the 

 posterior margin. The hinge consists of two diverging teeth in 



