Notices of Memoirs — Islands and Coral Reefs of Fiji. 407 



uniform height throughout, and with no posterior oblique attenua- 

 tion. In referring to the stratified Quaternary deposits at Ombos 

 (= Kom Ombo), Leith Adams remarks that they measured 80 or 

 90 feet in height, but so far as he could ascertain yielded no organic 

 remains. Mr. Willcocks' discovery of this new JJnio, from probably 

 the same spot at about 8 metres above the present high Nile, adds 

 a further interest to this locality. The specimens were found 

 associated with vertebrate remains (reptiles, fishes, etc.). 



Horizon. — Post-Pliocene (Fluviatile Deposits). 



Distribution. — Nubia : Second Cataract. Egypt : Kom Ombo 

 (= Ombos of Leith Adams), lat. 24:° 2' 30" N., at about 8 metres 

 (= rather more than 26 feet) above present high Nile. Coll. Geol. 

 Surv. Egypt (No. 647, Box No. 235). 



EXPLANATION OF PLATE XIX. 



Alectkyonia cucullata, Born, sp. Pliocene (Astian?), Moluk Hill. 

 Fig. 1. — Front view of two lower valves, united laterally. 

 Fig. 2. — Back view of a lower valve exhibiting the plications. 

 Fig. 3. — Fragment of the ligamental region of another lower valve, rather longer 



than usual, and evidently belonging to an older form than the other specimens. 

 Fig. 4. — Upper valve, interior. 

 Fig. 5. — Upper valve, exterior, showing obsolete plications. 



Planorbis Pfeiffeei, Krauss. Post-Pliocene, near Farshut ( x twice nat. size). 

 Fig. 6. — Profile of shell, showing the aperture. 

 Fig. 7. — Upper surface of shell, showing the depressed whorls. 

 Fig. 8. — Under surface of shell, showing the umbilicus and aperture. 



Melania tubbrculata, Miiller, sp. Post- Pliocene, near Farshut. 

 Fig. 9. — Front view of largest specimen, showing aperture. 

 Fig. 10. — Back view of the same specimen. 

 Fig. 11. — Magnified view of sculpture. 



EXPLANATION OF PLATE XX. 



Unio "Willcocksi, sp. nov. Post-Pliocene, Kom Ombo. 



Fig" 2 \ •'■''i^srior and exterior of right valve. 



Fig. 3. — Interior of a left valve. 



Fig. 4. — Exterior of a left valve, showing impression of the early shell. 



[Except where otherwise stated, the figures on both plates are drawn natural size.]] 



The Islands and Coral Eeefs of Fiji. By Alexander 

 Agassiz. (Bulletin of the Museum of Comparative Zoology, 

 Harvard College, vol. xxxiii.) 8vo ; pp. 168, with 120 plates. 

 (Cambridge, Mass., U.S.A.; May, 1899.) 



PROFESSOR ALEXANDER AGASSIZ deserves the thanks of 

 all naturalists for this splendid contribution towards the recently 

 much disputed subject, the origin and mode of formation of coral 

 reefs. This is an age of critical examination, and no man, however 

 beloved and esteemed amongst his fellow scientific men, can pro- 

 pound a theory which shall long remain unchallenged. That 

 Darwin's theory remained accepted and undisputed for fifty years 



