GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 411 



of a corallite about 3 mm. tall is about 4 mm., at its base about 5 

 mm., showing that although the diameter at the base of the free 

 corallite limbs is greater than it is at the calice, the increase in diame- 

 ter toward the base is rather slight. The costae on the free limbs 

 are low, subequal, closely crowded, between 40 and 48 in number, 

 relatively thick, as thick as or thicker than the intercostal furrows, 

 and closely beaded along the edges. The walls are thick. 



Septa, 3 complete cycles and a variable number of quaternaries. 

 The 6 primaries are larger than the other septa, extend to the colu- 

 mella, and bear paliform thickenings which are decidedly prominent 

 in those calices where they have been preserved; the secondaries are 

 somewhat shorter than the primaries; the tertiaries still shorter; and 

 the quaternaries, which may be completely developed in some sys- 

 tems, are still smaller; in some systems in many calices the quater- 

 naries are not distinguishable within the calices, but are represented 

 by small costae. 



Columella, a narrow, compressed style. 



Endotheca and exotheca, details of their character not clear in 

 the type. 



Locality and geologic occurrence. — Canal Zone, station 6016, in the 

 Emperador limestone, quarry, Empire, collected by T. W. Vaughan 

 and D. F. MacDonald. 



Type.—G&t. No. 324955, U.S.N.M. 



Genus SEPTASTREA d'Orbigny. 



1849. Septastrea D'Orbigny, Notes sur Polyp., p. 9. 



1849. Septastrea Milne Edwards and Haime, Ann. Sci. nat., ser. 3, Zool., vol* 



12, p. 163. 

 1857. Septast raea Milne Edwards and Haime, Hist. nat. Corall., vol. 2, p. 449. 

 18 — . Septastraea (part) de Fromentel, Intr. Etude Polyp, foss., p. 174. 

 1884. Septastraea (part) Duncan, Linn. Soc. London Journ., Zoology, vol. 18, 



p. 103. 

 1887. Glyphastraea Duncan, Geol. Soc. London Quart. Journ., vol. 43, pp. 24-32, 



pis. 1-3. 

 . 1888. Septastraea Hinde, Geol. Soc. London Quart. Journ., vol. 44, pp. 200-227, 



pi. 9. 

 1900. Septastraea Gane, U. S. Nat. Mus., Proc. vol. 22, p. 194. 

 1904. Septastrea Vaughan, Maryland Geological Survey Miocene, p. 444. 



Type-species. — Septastrea subramosa d'Orbigny, 1849=$. forbesi 

 Milne Edwards and Haime, 1849 = Astrea marylandica Conrad, 1841 = 

 Septastrea marylandica (Conrad) Vaughan, 1904. 



SEPTASTREA MATSONI, new species. 



Plate 86, figs. 6, 6a. 



Corallum incrusting surfaces of shells. The type incrusts part of 

 the surface of a Turritella shell. It is probable that the fully grown 

 coral 1 um may be massive or ramose. 



