218 PALEONTOLOGY OF OHIO. 



weathered. Lastly, from Cyathophyllum proper Streptelasma is distin- 

 guished chiefly, or solely, by the total absence of dissepiments and the 

 comparatively rudimentary condition of the tabulae. 



Streptelasma coeniculum, Hall. 



Streptelasma corniculum, Hall ; Pal. N. Y., Vol. I., pi. 25, figs, la, le. 



Streptelasma crassa, Ibid. ; pi. 25, figs. 2a, 2c. 



Streptelasma multilamellosa. Ibid, ; pi. 25, figs. 3a, 3c. 



Streptelasma parvula, Ibid. ; pi. 25, figs. 4, 4c. 



Streptelasma corniculum, Edwards andHaime; Pol. Foss. des Terr. Palaeoz., pi. 7, fig. 4. 



Corallum conical, slightly curved, or nearly straight, averaging from 

 one to four inches in length, and from ten lines to an inch and a half in 

 diameter. Septa numerous, from ninety to one hundred and sixty in 

 number, alternately large and small. The small septa rarely extend 

 much beyond the margin ; but the large ones extend to the center, in 

 approaching which they become more or less twisted, and unite with 

 one another, sometimes giving rise to a central mass of vesicular tissue. 

 Calice moderately deep. Septa very thick, and often appearing as if 

 composed of two lamellse. Tabulae remote and irregular, sometimes 

 elevated towards the center of the visceral chamber. No dissepiments. 

 A single septal fossette, usually placed on the curved side of the coral. 

 Epitheca exhibiting longitudinal ridges corresponding with the septa 

 within; otherwise smooth, or, rarely, with a few encircling shallow folds 

 of growth. 



This species — if all the specimens I have referred to it rightly belong 

 to it — is very variable in size, in the amount of curvature, and in the 

 number of septa. The following are the dimensions of a number of ap- 

 parently typical examples : 



1. Four inches long ; diameter at summit nearly an inch and a half; 

 one hundred and sixty septa, alternately large and small. This is the 

 largest specimen I have seen, but imperfect at its summit. 



2. Length over three inches ; diameter at summit fourteen lines ; one 

 hundred and twenty-six septa, alternately large and small. 



3. Length one and a half inch ; diameter at summit fourteen lines ; 

 one hundred and twenty-six septa, alternately large and small. A bro- 

 ken specimen. 



4. Length one inch and a half; diameter at summit ten lines; one 

 hundred and fourteen septa, alternately large and small. 



