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PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 83 



Remarks. — This species is readily distinguished by the low sub- 

 hemispherical corallum with a small point of early attachment and 

 by the septal arrangement. The only American species to which 

 it might be related is E. conradi Vaughan (1900b, p. 183) from the 

 upper Eocene of Virginia and Mississippi, which has a much 

 thicker wall and four cycles of septa. 



Family ACROPORIDAE Verriil 



Genus DENDRACIS Milne Edwards and Haime, 1849 



DENDRACIS CANTABRIGIENSIS Vaughan 



Dendracis cantahrigiensls Vattghan, 1899, p. 248, pi. 41, figs. 3, 5, 6 {non 4) ; 

 1919, p. 194.— Fexix, 1925, p. 2GS. 



Occurrence. — Specimen 1 is from the Yellow limestone at Spring 

 Mount; specimens 2 and 3 are from the same formation in the 

 Cambridge district, Jamaica (Trechmann collection). 



Remarks. — Two small fragments and a small block containing 

 several fragments, all from the Trechmann collection, have been 

 identified by Dr. Vaughan wath his species. There are no notable 

 departures from his published description. 



Measurements. — As follows : 



Genus ACTINACIS d'Orbigny, 1849 



ACTINACIS SAWKINSI, new species 



Plate 4, Figure 5 ; Plate 5, Figure 7 



Description. — Corallum massive, upper surface convex, marked 

 by low rounded gibbosities, under surface irregularly concave, the 

 whole being composed of superimposed laminar layers. Corallites 

 small, 1.2 to 1.5 mm in diameter, separated by less than their own 

 diameter of coencncliyme. The coenenchyme is composed of per- 

 forate septo-costae, which are united by synapticulae to form a 

 porous reticulum. Corallite w^alls distinct, very porous, formed by 

 a single ring of large synapticulae connecting the thickened outer 

 trabecular elements of the septa. The septa are straight, well de- 

 veloped, less in thickness than the interseptal loculi; they arc al- 



