R. BuUen Newton — Miocene Shells from Egypt. 205 



OSTREA FUCHSIAjSTA,! gp_ no^. (PI. IX, Figs. 1, 2.) 



Description. — Lower valve convex, rounded anteriorly, and 

 produced in rear ; summit truncate ; surface divided up into a series 

 of divergent plications, between each being a wide and conspicuous 

 depression or channel ; the plications at the different periods of 

 growth becoming modified into hollow, narrow, and elevated spines. 

 Near the posterior margin the interior of the valve exhibits 

 a large, deep, and nearly round muscular scar with concentric 

 markings ; the ligamental area is small, triangular, and curved 

 posteriorly ; obscui-e marginal denticulations are present on each 

 side of the shell near the ligamental area. 



Dimensions. — Height, 80 mm. ; length, 100 mm.; diameter, 40 mm. 



Remarks. — The above characters are drawn up from a single 

 lower valve which was found in association with Ostrea vestita 

 and 0. Virleti. Its very convex form and peculiar spiny character 

 of the external surface appear to separate it from other species of 

 Ostrea. It slightly resembles 0. foliosa, Brocchi, from the Italian 

 Pliocene, but in that species the outer surface is sulcated and 

 fluted, and rarely shows elevated spines. The specimen, encrusted 

 in places with a Celleporoid Bryozoa, is of fawn colour and entirely 

 free from matrix. I have ventured to name this shell after 

 Dr. Theodor Fuchs, one of the first authorities on the Miocene 

 conchology of Egypt. 



Horizon. — Miocene (Tortonian). 



Distribution. — Egypt : Camp 19. Coll. Geol. Surv. Egypt, 

 No. 342, Box No. 13° a. 



OSTREA VESTITA ?, Fuchs. 

 Ostrea vestita, Fuchs: Paleeontographica, vol. xxx (1883), p. 44 (26), pis. xi (vi), 

 xii (vii), figs. 1, 2. 



Remarks. — Among the Egyptian specimens are two lower valves 

 of an oyster referred doubtfully to this species. They are of oval- 

 oblong shape, very strong and thick, and apparently composed 

 of regular foliaceous growths, the exposed edges of which do not, 

 however, bear the fimbriated markings observable in Fuchs' figures 

 of the type, though the absence of this character may be noted in his 

 fig. 2 of pi. xii. In other details the specimens agree with 0. vestita. 



Horizon. — Miocene (Tortonian). 



Distribution. — Egypt : Siwa (Fuchs) ; Camp 19. Coll. Geol. 

 Surv. Egypt, No. 342, Box No. 13a. 



OSTREA (ALECTRTONIA) VIRLETI, Deshayes. 

 Ostrea Virleti, Ostrea pseudo-edulis, Ostrea excavata, Deshayes : Exped. Sci. Moree 



vol. iii (1883), pt. 1 [MoUusques], pp. 122-4, pi. xxi, figs. 1-6. 

 Ostrea excavata, Ostrea Virleti, Abich, " Ueber Steinsalz, etc., Russischen Armenien " : 

 Mem. Ac. Imp. Sci. St. Petersbourg, ser. vi, vol. ix (1859) (= pt. 1, vol. vii, 

 Mem. Sci. Phys. Nat.), pp. 124-6, pi. ii, figs. 1, 2 ; pi. iii, fig. 1 ; pi. y, figs, i^ 2! 

 Ostrea Virleti, Fuchs : Denk. Akad. Wiss. (Wien), vol. xii (1879), pt. 2, p. 106, 

 pi. iv, figs. 1-9 ; Paleeontographica, vol. xxx (1883), pp. 43 (25), 61 (43)^ 

 pis. ix (iv), X (v). 



Description. — Shell of variable form, mostlj-^ orbicular or 

 oblong; valves prominently plicated, margins more or less flexuous ; 

 1 Non Ostrea Fiwhsi of A. de Gregorio, 1884. 



