438 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



Fourth cycle of septa normally complete, a few quinarie3 in large calicea. 



Columellar fossa not very deep; lesser diameter of calices from 4 to 6 mm.; tertiary 

 septa fuse to secondary distinctly back from the columella; about 4 septal teeth 

 to 1 mm. (fourth cycle of septa incomplete in some calices). 



7. S. hillsboroensis, new species. 

 Columellar fossa deep, rather narrow at the bottom; calices 3 to 5 mm. in diam- 

 eter; tertiary septa normally fuse to secondaries distinctly back from the 



columella; 6 to 8 septal teeth to 1 mm 8. 1 S. siderea (Ellis and Solander). 



Four complete cycles and normally some quinaries septa. 



Columellar fossa rather deep and wide bottomed; calices 5 to 7, even 8 mm. in 

 diameter; tertiary septa fuse to secondaries near or at the columella; septa and 

 septal teeth less numerous than in No. 11; septal teeth not transversely com- 

 pressed and frosted as in No. 10 9. S. silicensis, new species. 



Columellar fossa shallow, calices widely open; calices 5 to 6.5, even 8, mm. in max- 

 imum diameter; tertiary septa fuse to secondaries near the columella; septal 

 teeth numerous, crowded, transversely compressed, finely frosted. 



10. S. dalli, new species. 

 Four complete cycles of septa and many quinaries. 



Columellar fossa shallow or rather deep and narrow; calices from 4.25 to 6, up to 

 8.5 mm. in maximum diameter; septa numerous, up to 91 in large calices, thin 

 crowded; septal teeth small, crowded 11. S. conferta (Duncan). 



The foregoing is intended to aid in the preliminary placing of a 

 species with reference to the other members of the genus, and is not 

 a complete summary of characters. The details of the mural charac- 

 ters, the relative thickness and crowding or remoteness of the 

 septa, the septal trabeculae, the dentation of the septal margins, the 

 distribution and size of the synapticulae, and the details of the 

 columella, all need to be considered. For these additional details 

 the descriptions and the rather elaborate illustrations must be con- 

 sulted. 



1. SIDERASTREA PARIANA (Duncan). 



1867. Astraea pariana Duncan, Geol. Soc. London Quart. Journ., vol. 24, 

 pp. 14, 24. 



Original description. — "The corallum is massive and rather tall 

 and its upper surface is flat. The corallites are slender, tall, crowded, 

 and equal. The calices are small,- and the fossa is rather deep. The 

 columella presents one rounded process. The septa are in six sys- 

 tems and there are three cycles; they are alternately large and small, 

 and the smallest usually unite to the large septa; they are faintly 

 dentate. The laminae present on their sides sets of granules in 

 horizontal but wavy lines. The endotheca is rare. The diameter 

 of the calices is one-twelfth inch [2 mm.]." 



Locality. — St. Croix, Trinidad. 



1 S. siderea var. dominicensis, new variety, is like S. siderea except that it has larger calices and corre- 

 spondingly a number of quinary septa. 



