Dr. J. TF. Gregory — An Egi/ptian Millejjoroid Coral. 341 



well developed. The pores are mostly irregular in distribution, but 

 some occur in small cyclo-systems and others in linear series, 

 separated by sinuous, branching depressions. Canals short and 

 broad. 



DisTKiBUTiON. — Cretaceous : Egypt. 



Millestroma Nicholsoni, nov. 



Diagnosis. — Coenosteum ovoid, formed of a thick encrustation. 

 The surface is marked in places by low humps and knobs ; otherwise 

 it is smooth. Cyclo-systems widely scattered ; the macropore 

 (gastropore) is not much greater than the micropores (dactylopores), 

 of which there are usually six or seven in" a system. The surface is 

 also marked by irregular, sinuous, radial valleys ; on the ridges 

 between them the pores are often linear in arrangement. Tabulaa 

 abundant. The radial pillars are irregular in course. 

 Dimensions. 



Length of ccEnosteum ... ... ... ... ... 83 mm. 



Diameter of ccenosteum ... ... ... ... 40 mm. 



Diameter of pores about • 15 mm. 



DiSTKiBUTiON. — Turonian : Abu Eoasch, near Gizeh, Egypt ; Coll. 

 Geol. Surv. Egypt, No. 61. 



Desckipxion of Figures. — PI, XIII, Fig. la, half of the coenosteum, 

 nat. size, showing the knobbed surface (a) and the sinuous grooves (b); 

 Fig. lb, transverse section across the same specimen, nat. size, 

 showing the gastropod which forms the nucleus of the ccenosteum ; 

 Fig. Ic, part of the surface of the same specimen, x 8 diam., showing 

 a cyclo-system at a and a weathered area at b ; Fig. Id, part 

 of a horizontal section across the same specimen, x 8 diam., showing 

 the flexuous horizontal canals at c ; Fig. le, part of a vertical 

 section across the same specimen, x 8 diam., showing the irregular 

 pillars (p), the absence of concentric, horizontal laminae, the 

 abundant tabulse (<), and the secondary crystals of calcite (c). 



Affinities. — This fossil most nearly resembles in its general 

 characters the Stromatoporoid described by Nicholson as Hermato- 

 stroma.^ With this genus it agrees in the presence of the horizontal 

 flexuous tubes (cf. Nicholson, op. cit., pt. i, 1886, fig. 16, p. 106) ; 

 in the presence of the branching and somewhat irregular vertical 

 pillars (cf. Nicholson, op. cit., pt. i, p. 42, fig. 1, B, and pt. iv, 

 pi. xxviii, fig. 9, with PL XIII, Fig. le) ; and with the linear series of 

 pores, separated by irregular, somewhat radial grooves (cf. Nicholson, 

 op. cit., pt. iv, pi. xxviii, fig. 13). Hermatostroma, however, has not 

 the cyclo-systems shown on PL XIIl, Fig. Ic; and Millestroma has not 

 the well-developed concentric laminte formed by horizontal " arms " 

 from the vertical pillars. In both these respects the genus resembles 

 Ilillepora more than the Stromatoporidee. Cyclo-systems resembling 

 those of this specimen are shown by Moseley in a specimen named 

 Millepora nodosa. Millestroma is therefore an intermediate form 

 between the Palaeozoic and Cainozoic Milleporoid Hydrocorallin^e. 



^ H. A. Nicholson, " A Monograph of the British Stromatoporoids," pt. i (1886), 

 p. 105. 



