MIOCENE MOLLUSCA OF LAKE UEMI. 441 



Ostrea Virleti, 0. excavata, A}m.ch.,M.6vix. Ac. Frnp. Sci. St. Petersbourg, 

 1858, ser. 6, vol. vii. pi. 2. figs. 1, 2 ; pi. 3. figs. 1, 2 ; pi. 6. figs. 1, 2 ; 

 OT- 124 (66), 125 (67). 



Ostrea Virleti, Fuclis, Denksclir. K. Akad. Wiss. 1879, vol. xli. pt. 2. 

 pi. 4, p. 106 ; and PaleeontograpHca, 1883, vol. xxx. pi. 9. (4), pi. 10. (5), 

 p. 43 (25). 



Ostrea {Alectryonia) Vh'leti, R. B. Newton, Geol. Mag. 1899, p. 205. 



This is a most abundant species in Persia, occupying the 

 topmost bed of the Miocene section at Koyun Dagbi island, as 

 given by Dr. Abich in bis 1882 work. It is a form of some- 

 what variable shape, though exhibiting external plications on both 

 valves, which places it in the genus Alectryonia. These plications 

 may sometimes be more or less obsolete according to age and 

 wear ; the valves are mostly depressed, though the excavata form 

 has a very convex lower valve. Mr. Griinther's specimens are 

 fairly typical of the species and correspond with Dr. Abich's 

 figures of the same. 



The species has been previously recorded from the Miocene 

 rocks of Morea (Deshayes) ; Siokuh Mountains, Persia (Fuchs) ; 

 Egypt (Fuchs) ; Azores &c. (Mayer-Eymar) ; Crete (Eaulin) ; 

 Cyprus (G-audry) ; Malta (Wright) ; and a variety of this species 

 is recorded from the Pliocene deposits of Altavilla, Italy, by 

 Gregorio (Boll. Soc. Mai. Italia, 1884, vol. x.). 



Localities. Several specimens were obtained from the beach of 

 the island of Koyun Daghi; and one fragmentary valve came 

 from the cliff-section of the same island. 



Formation. Miocene, probably about the age of the Leithakalk, 

 which is Tortonian. 



Pecteis" Beudanti, Basterot. (Plate 39. fig. 2.) 

 Pecten Beudanti, Basterot, Mem. Soc. Hist. Nat. Paris, 1825, vol. ii. 

 part 1, pi. 5. fig. 1, p. 74 ; Homes, Abhandl. k.-k. Geol. Reichs. 1867, 

 vol. iv. pi. 59. figs. 1-3, p. 399 ; T. Fuchs, Denksehr. K. Akad. Wiss. 1879, 

 vol. xli. pt. 2. p. 105 ; R. B. Newton, Geol. Mag. 1899, p. 207. 



A large convex lower valve, contained in this collection, appears 

 to be referable to P. Beudanti. The fine, striated sculpture of 

 the surface, however, through erosion by water or weathering, so 

 conspicuous a feature of this species, is almost obliterated, 

 although it can be obscurely traced in places. In every other 

 respect it agrees with Homes' interpretation of Basterot's shell. 

 It is very transverse (dimensions in millimetres = height 87, 

 length 110, depth 35), and bears about 16 wide plano-convex 



LINN. JOITEN. — ZOOLOGY, YOL. XSVII. 33 



