INDIANA PALEONTOLOGY. 52, 



ancy between them. This feature is occasionally seen in C- dichotoina, the 

 most regular species of the genus, and is common in C. distorta. 



When the corallites are united by the epithecal prolongations, a rugose 

 surface is produced from the wrinkled character of the epitheca. Otherwise 

 the surface is smooth, showing only fine concentric growth lines. When the 

 corallites grow close together, they generally become inseperably united, and 

 not infrequently the original circular section of the tube will be variously mod- 

 ified or distorted, and often become concave on the side of contact. 



The less frequent development, in this species, of the cysts, is a character- 

 istic feature. They are best visible in the calicinal portions, for as the known 

 specimens of this species are all silicified, the interior structure has become more 

 or less modified, and some of the cysts have been filled. There is, as in all the 

 species of the genus, a complete absence of tabulae, the corallites remaining 

 open throughout, and united to their parent basally at least during the greater 

 part of life. In many individuals the connecting pore is probably never closed, 

 in others a sort of partition is formed over it by the extensive growth of spines. 

 When the daughter corallite becomes separated from the mother tube, the pore 

 may be covered by the formation of a cyst wall over it. Occasionally ad- 

 joining corallites have been found to be traversed by a single pore, this un- 

 doubtedly being a case of aborted budding. The septal spines appear generally 

 much shorter than in the Devonian species, in this respect, and in the diminu- 

 tion of the cysts, approaching Monilopora. In a few cases, however, spines 

 comparable to those of C- dichotoma and C. distorta have been observed. In 

 some cases the interior of the wall appears perfectly smooth, the fine papillose 

 spines being probably destroyed during the process of crystallization. 



This species is closely related to C- distorta, Grabau, but I do not think 

 that the two are identical. The profusely branching specimen figured on plate 

 3, fig. 7, Vol. 28, No. 16, Boston Soc. Nat. Hist. Proceedings, and referred to 

 C' distorta, has many characters of the present species, and forms a connect- 

 ing link between the two. Though parallelisms in form occur, the structure of 

 the two specie? is sufficiently distinct. The present species is also somewhat 

 smaller than the prevailing forms of C- distorta- 



Horizon and Localities, — In the Warsaw division of the St. Louis group, 

 Lower Oarbonian ; Lanesville, Harrison county, Indiana. 



Types in the collection of Mr. G. K. Greene. 



ROMINGEI^IA CYSTOIDES, N. Sp. (Grabau.) 



Plate 20. Figs. 19-23. 

 Corallum compound, erect, free except basally, consisting of numerous 



