392 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



and appear to be covered with a fine epitheca. and their course is often in a curve. 

 In transverse and vertical sections the costae are seen to project far from the wall, 

 and to be marked by oblique and abundant exothecal disseiDiments; the tertiary 

 costae being much less projecting than the others. The columella is large, lax, and 

 papillary. The fossa is deep. The endotheca is not well developed, but the dis- 

 sepiments extend to close to the calice. Diameter of calices one-fifth inch [5 mm.]; 

 height of the corallum 9.10 inches [22.5 mm.]. The costae are very marked in this 

 species, and with the papillarjr columella and short calices distinguish it from its 

 allies; it is related both to Astraea cylindrica nob., and to Astraea cavernosa 'Edwards 

 & Haime. 

 From the Mvaje shale, San Domingo. Coll. Geol. Soc. 



Duncan's remarks on the affinities of this coral are correct, and 

 in a previous paper I referred it to the synonymy of 0. cavernosa} 

 The type of the species is represented by plate 97, figure 1. The 

 costae are similar to those of 0. costata, but the calices are much 

 smaller. It wiU be noted in the figure that around the calicular 

 margins the costae are subequal and that lower down on the corallite 

 limb those corresponding to the last cycle of septa become smaller 

 while the alternate costae become more prominent and extend on to 

 the intercorallite areas. The costal beading is rather coarse, therein 

 resembling 0. tampaensis, which has larger calices. As predictions 

 as to the ultimate fate of coral-names are admittedly hazardous, 

 I will only remark that it seems to me from the material available 

 for study that 0. hrevis is a distinct species; but a specimen from the 

 "silex" beds near Tampa, Florida, so nearly bridges the gap between 

 0. tampaensis and 0. hrevis that doubt is cast on their specific distinct- 

 ness. Should the two supposed species ultimately be combined 

 under one name, of course 0. hrevis, it being the older name, would 

 persist, and 0. tampaensis would become either a synonym or would 

 be reduced to varietal or subspecific rank. 



13. ORBICELLA INSIGNIS (Duncan). 



Plate 98, figs. 1, 2, 2a. 



1867 Heliastraea insignis Duncan, Geol. Soc. London Quart. Journ., vol. 24, pp. 

 19, 24, pi. 1, fig. 4. 



Original description. — "The corallum is large, and the corallites 

 also; they are wide apart, are circular in transverse outline, and are 

 very equal in size. The wall is stout as regards the septa and costae, 

 but thin in comparison with the diameter of the corallites. The septa 

 are delicate, wide apart, long, slightly thicker at the wall than else- 

 where, straight, and the primary septa are hardly any broader than 

 the tertiary. There are three cycles of septa in the six systems, and 

 rarely a septum of the fourth cycle is noticed in half of a system. 

 The primary and secondary septa are of equal length, and the tertiary 

 extend far in towards the columella. The columella is small. The 

 costae are long, slender, often bent, almost equal, and of about the 



1 deolog. Reichs. Mus. Leiden, scr. 2, vol. 2, pt. 1, p. 29, 1901. 



