530 J. W. Gregory & Jean B. Trench— 
species in calicular characters; but its calices are much more widely 
separated, the centres being from 10 to 11 mm. apart, and the 
corallum is dendroid. 
An Eocene species, 4. digitata, from Borneo, has been described by 
Fritsch (1875, p. 129, pl. xvii, fig. 7); it differs very considerably 
from A. maitlandi; its calices are smaller, the pali are more 
prominent and regularly arranged around a small columella, which on 
the surface appears styliform ; the corallum, moreover, is dendroid. 
Actinacis sumatraensis (Tornquist), 1901. (Pl. XXI, Fig. 1s) 
Neostroma sumatraensis, Tornquist, 1901: ‘‘ Ueber mesozoische Stromato- 
poriden,’’ Sitz. k. preuss. Akad. Wiss., 1901, pp. 1117-20, figs. 1-5. 
Actinacis sumatrensis, Gerth, 1909: ‘*‘Echte und falsche Hydrozoen aus 
niederlandisch-Indien,’’ Sitz. Niederrhein. Ges. Natur. u. Heilkunde zu 
Bonn, Abt. A, 1909, pp. 21-3. 
This species is represented by one specimen, No. 14. It agrees 
closely with the Sumatran Cretaceous species A. sumatraensis 
(Tornquist), though the septa in the latter are thinner, longer, 
and more irregular, while the calices are slightly larger and closer 
together. In A. cymatuclysta (Felix, 1906, p. 43, pl. ili, figs. 4, 4a) 
the calices are almost of the same size and shape, but the primary 
septa at least reach the columella, which is feebly developed, though 
the pali are distinct. 
Porirrs, Lamarck, 1816. 
Porites deshayesana, Mich. (Pl. XXII, Figs. 2a, b.) 
Porites deshayesana, Mich., 1844, p. 164, pl. xlv, fig. 4. 
The collection includes one specimen (No. 28) of a Porites which 
agrees in early all respects with the above species. If, however, 
Bernard (1906, p. 109) were right that the calices of P. deshayesana 
are less than 1mm. in diameter, it would differ in that important 
respect. Bernard states that his estimate of the dimensions is based 
on Michelin’s original figure, in which, according to our measure- 
ments, the corallites are shown as at least 1°5 mm. in diameter. 
They thus agree with those of the New Guinea Porites. The 
character of the septa are shown by the accompanying drawings of 
three corallites from a section (see Text-figure). 
Sse ve} 
& ee 638 
Porites deshayesana, Mich., var. inequisepta, n. var. Transverse 
sections of three corallites. Upper Fly River, New Guinea. 
The septa appear to be thicker and more unequal in size than in 
the typical form of the species. Accordingly we feel bound on that 
character to separate this coral as a distinct variety and name it 
var. dnequisepta. 
Amongst other Eocene species this Porites agrees by its ill-defined 
columell: and indistinct wall with Porites heberti, Ed. & H., sp. (1850, 
