92 EOCENE AND LOWER OLIGOCENE CORAL FAUNAS. 



the second cycle are notched 0.5 or 0.75 nun. above the base. There are 

 costse corresponding- to the septa of the third cycle, and after the second 

 cycle of septa is fully develo})ed rudimentary costse usually exist. The 

 septa developed between the first and second cycles of septa do not always 

 correspond to the rudimentary costse found between those two cycles. 

 When a septum develops in this way, a costa corresponding to it is devel- 

 oped. Therefore we have both a rudimentary costa and a regular costa 

 alonsrside each other in the same interval between two costse of the first 

 and second cycles, respectively. The intercostal furrows are always per- 

 forate, and when the i-udimentary costje are not present there are double 

 rows of perforations. 



A distinguishing feature of this species is that in the basal portion the 

 costal terminations are not enlarged. Of the 12 costse that extend to the 

 base, 6 do not change at all and 6 are simply notched about 0.5 mm. above 

 the base. 



The septal aiTangement is simple: it is six systems and tln-ee cycles. 

 In two systems of the larger sjiecimen that I have examined the third cycle 

 is not complete. The septa of the third cycle fuse by their margins to the 

 sides of those of the first cycle. Excepting the first cycle, the septa are 

 thin; their sides are beset with small spines. 



The specimens are not well enough preserved to permit the details of 

 the columella to be fully made out, but we can be sure that the upper ter- 

 mination is a style and not a strongly stellate pillar, the rays of which join 

 the inner ends of the septa of the first cycle, such as is characteristic of T. 

 pharetra and T. wautuhheensis. The columella of T. insignifica has a rather 

 prominent upper termination. Diametei", 2 mm.; length, 3.5 mm. 



Locality. — Old Red BlufiF Station, 3i miles south of Shubuta, Mississippi. 

 (F. Burns, collector.) 



Geologic occurrence. Red Bluft' bcds. 



Types. — United States National Museum. 



The character of the (columella above noted, the peculiarities of the 

 costfe in its basal portion, and its very small size serve to distinguish this 

 species. 



