Prof. J. W. Gregory— Fossil Corals from Egypt, etc. 53 



■developed columella, the septa of the first and second cycles reach 

 the columella. Exotheca coarsely vesicular, abundant. 

 Columella well developed. 

 Dimensions : — 



Type-specimen (a fragment 

 of a much larger mass) 



H1862. H1856. 



Length 128 mm. ... 155 mm. 



Width 75 ,, ... 120 ,, 



Thickness 40 ,, ... 95 ,, 



Corallites : — 



Diameter ... 4mm., occasionally 5 ,, ... 4 ,, 



Calicinal centres : — 



Distance ... 6-9 mm., average 7 ,, ... 5 aud 7 mm. 



Distribution. — Miocene. West flank of Jebel Mellaha, H 1862 ; 

 H 1856. Eeef No. 2, plateau between Camps 27 ami 28, Wadi 

 Belih, Abu Sha'ar, H 18186. " Beach Plateau," Abu Sha'ar, H 1780a. 



Figures. — PI. VI, Fig. 3, part of the surface of H 1862, by 1^ diam. 

 Fig. 4, some corallites of H 18186, by 2 diam. 



Affinities. — This species is a typical Orbicella with corallites of 

 medium size. It is nearest to 0. defrancei (Ed. & H.) ' from the 

 Miocene of Bordeaux, Turin, and Asia Minor. But it differs as the 

 corallites are much smaller, having an average of 4Jmm. in diameter 

 instead of 6-7 mm., and in most cases the corallites have only 

 3 cycles of septa. 0. defrancei has a fourth cycle, sometimes 

 incomplete ; but 0. mellahica has 3 cycles with an occasional 

 corallite with a rudiment of the fourth. In 0. ImmpJireysi, Felix,^ 

 the diameter of the calices is only 2"5 to 3 mm. 



It differs from 0. schweinfurtlii, Felix,^ in the same characters as 

 those whereby it differs from 0. defrancei. 



Of the three Miocene Orhicellce from Sind described by Duncan, 

 it is nearest to 0. digitata, Dune.,* which has smaller calices and 

 a smaller columella, aud an average distance between the calicinal 

 centres of only 4 mm. 



2. Orbicella. sohweinfurthi (Felix), 1884. (PI. VI, Fig. 5.) 



Seliastrcea sohweinfurthi, Felix, 1884, Kor. agypt. Tert. : Zeit. dent. geol. Ges., 



vol. xxxvi, p. 449, pi. v, fig. 5. 

 Orbicella schiveinfurthi, Gregory, 1898, Egj^^t. Foss. Madrep. : Geol. Mag., Dec. IV, 



Vol. V, p. 246, PL IX, Fig. 3. 



Distribution. — Miocene : Wadi Eamlieh (Felix) ; nortli side of 

 Jebel Attaka, near Suez (Gi'egory) ; west flank of Jebel Mellaha, 

 H 1862 ; " Beach Plateau," Wadi Belih, H 1782 ; " Beach Plateau," 

 Abu Sha'ar, H 1818. 



^ Edwards & Haime: Ann. Sci. nat., ser. iii, vol. xii (1850), p. 106 ; Hist. nat. 

 Cor., vol. ii, p. 465. 



- Felix, Stud. tert. und quart. Kor. agj-pt. und Siuaihalbinsel : Zeit. deut. geol. 

 Ges., vol. Ivi (1904), p. 171, pi. x, fig. 2. 



3 FeUx, Korallen agypt. Tert. : Zeit. deut. geol. Ges., vol. xxxvi, p. 449, pi. v, 

 fig. 5. 



■* P. M. Duncan, Mon. Foss. Corals and Alcyonaria of Sind : Pal. Ind., ser. xiv 

 (1880), pp. 90-91, pi. xxi, figs. 7-8. 



