n6 



Cincinnati Society of Natural History. 



Quite a number of species have been described from our group, 

 but they do not seem to be founded upon very good characters. Those 

 that seem worthy of specific rank are given below. 



78. — M. (Dekayia) aspera. Edw. & Haime, 1851. 



Corallum dendroid, branching frequently and dichotomously and 

 arising from a broad basal expansion ; branches varying from two to 

 eight lines in diameter according as they are near the top or at the 

 base of the corallum ; surface usually with low and rounded monti- 

 cules, four or five in about one-half inch ; formed of cells very little 

 larger than the average and often with a limited number of smaller 

 interstitial cells; spines conspicuous with thick walls and small cavity 

 occupying angles of cells; corallites polygonal; tabulae wanting in 

 the axial region and remote in the peripheral. (Pol. Foss. des Terr. 

 Pal., 1851, p. 277. Ulrich, Jour. Cin. Soc. Nat. Hist., vol. 6, 1883, 

 p. 149.) (Chcetetes attritus Nich., Quar. Jour. Geol. Soc. Lond., vol. 

 30, 1874, p. 503 : Dekayia multispinosa Ulrich, Ibidem, p. 154.) 



Locality. — Cincinnati. 



Remarks. — In a previous paper several other synonyms were 

 given for this species.* While the species is a variable one it has 

 been deemed best in the present instance to increase the number of 

 species, perhaps unwisely. All seem to agree that Nicholson's attrita 

 is the same as D. aspera, and D. multispinosa differs mainly in a larger 

 number of surface spines. Internally the structure of the two is the 

 same. 



79. — M. (Dekayia) maculata James, 1881. 



a. b. c d. 



Fig. 11. 



Fig. 11. — M. (Dekayia) maculata James: a, specimen nat. size; b, surface x 18; c, 

 tangential section, x 18; d, longitudinal section, x 18. (After an unpublished plate by Ulrich.) 



* Jour. Cin. Soc. Nat. Hist., vol. I, 1888, p. 28. 



