GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 



353 



O.aldrichi, andO. ? smithi shoukl bo indicated. The species mentioned 

 have axial corallites and generically resemble Archohelia except in 

 the details of the inner ends of the septa. The type-species of 

 Astrhelia (the correct spelling of the name, instead of Astrohelia) is 

 Madrepora palmata Goldfuss, which has no definite axial coraUites, 

 and I have seen no pah or pahform lobes on its septa. The species 

 to which I applied the names Astrohelia neglecta and A. hurnsi, as 

 they possess axial corallite should be taken out of the genus 

 Astrlielia. As it is not practicable just now to revise critically the 

 Eocene and lower Oligocene species listed above, it will here only be 

 mentioned that they probably should be transferred to Archohelia. 



ARCHOHELIA LIMONENSIS, new species. 



Plate 80, figs. 1, la, \h, 2, 3. 



Corallum composed of relatively slender branches. The following 

 are measurements of the cotypes : 



Dimensions in millimeters of cotypes of Archohelia limonensis. 





Branch. , 



Length. 



Diameter. 



Calices. 





Lower 

 end. 



Upper 

 end. 



Diameter. 



Exsert. 



1 



25 

 31 

 33 



4.5 

 4.5 

 4 



4 

 4 

 3.5 



2. 5-3 ; 1-3. 5 



2 



' 



2-2.6 

 2.3-3 



0. 5-3. 5 



3 



1-7 







The cavity of the axial coraUite is about 2.25 in diameter. The 

 foregoing tables give the dimensions and amount of the projection 

 of the radial calices — the diameters stated are as measured from the 

 outside of the walls. The distance between adjacent calicular mar- 

 gms is about 2.5 mm. on branch No. 2; in extreme cases it ranges 

 up to as much as 7 mm., as between some calices on branch No. 3. 

 The arrangement is in more or less defuiite spirals. Subequal or 

 sHghtly alternating costae, with closely granulate surfaces, cor- 

 respond to all septa just below the calicular edges; lower down on 

 the coraUite hmbs they flatten and become subequal; they may 

 continue on the coeneuchymal surface or disappear. The calicular 

 cavities are excavated; moderately deep, about 1.5 mm. 



Septa normally in three complete cycles ; primaries as a rule shghtly 

 larger than the secondaries, both cycles reach the columella, and 

 have subequal, slightly exsert upper margins; tertiaries smaller than 

 the secondaries and have lower upper margins. Inner edges of the 

 tertiaries usually free, but m some systems they fuse to the sides of 

 included secondary septa. Single or double paliform teeth on the 

 inner ends of the primaries and secondaries. Septal faces closely 

 granulate. 



