NORTH AMERICAN PALEONTOLOGY. 265 



Nicholson, H. Allbtne — Coutinued. 



pillars and concentric lamin;e ; c. Variations in tbe structure of these ; 

 d. Tlie intcrlaniinar spaces; e. The zotiidal tubes; /. The astrorhizse; 

 g. The astrorhizal tabuhe ; h. The axial tubes; i. The epitheca ; j. The 

 surface; k. The reproductive organs. 



III. Systematic position and affinities of the stromatoporoids. 



IV. Siietch classification. 



V. Families and genera of the stroniatopoi'oids : (1) Actinostromidas. (2) La- 

 bechiidic. (3) Stromatoporida-. (4) IdiostromidiB. 



VI. The nature of " Caunopora." 

 The following is a notice of the American genera and species : 



Actiiioslromida', Nich. 



Actinofttroma gen. nov., Stromatopora, Auctt. 



Clathrodictyon, Nich. and Mur. Tyi)e C. vesiculosum, N. and M. Clinton and Ni- 

 agara formation. In America there is also C. ceUulosum N. and M. from the 

 Corniferous limestone. 



StuIodiGtyo)!, Nich. and Mur. Type S. cohimvare, Nich. From the Devonian of 

 North America. 



Lahechida', Nich. 



Labechia, Edwards and Haime, ISrA. Type L. conferta, Lonsd. Two species at 

 least of Lower Silurian age occur in North America, L. Canadensis, Nich. 

 and Mur., Trenton limestooe, and L. Ohioensis, n. s., Cincinnati group. 



Dictyostroma, Nich. Type D. undulatum. Niagara limestone. 



Beatricea, Billings. Types B. itndulaia and B. nodnloso. The balance of evi- 

 dence seems to the author to be in favor of regarding Beatricea as an ab- 

 normal type of the Stromatoporoids. 



Siromatoporidw, Nich. 



Stromatopora, Goldf. (emend.). Type S. conccntrica. Refers to this genus his 

 own genus, rachystroma, from the Niagara limestone. 



Stromatoporella, nov. gen. Type S. cjranuJata, Nicli. From the Hamilton and 

 Corniferous formations of western Canada. Refers to this genus probably 

 Stromatopora nnUiporoides, Nich., from the Devonian, and the allied or iden- 

 tical Cwnostroma incrnstans, Hall and Whitf., from the Devonian. 



Syringostroma, Nich. Type S. densum. 'Nich. From the Devonian rocks of Ohio. 



Idiostromid<r, Nich. 



Idiostroma, Winchell, founded for the reception of I. ccespitosum and /. gor- 

 diaceiim, from the Devonian rocks of North America. 



Considering that the embedded tubes constitute the essential feature upon 

 which Caunopora, Phill., and Biapora., Berg., were founded, the author 

 thinks that the facts render it absolutely certain that these names can not 

 be retained as names of genera. 



Concludes that "the fossils ordinarily called ' Caunopora' and ' Biapora' are 

 the results of the combined growth of some slromatoporoid with some 

 coral, the former usually being a s'pecies of Stromatopora or Stromatoporella, 

 and the latter generally belonging either to Syringopora or to Aitlopora 

 We must also conclude, however, that there are other fossils in general 

 aspect exceedingly similar to the ordinary ' Caunopora,' in which the em- 

 bedded tubes really do belong to the organism in -which they are found, as 

 we have seen to be the case in Idiostroma oculoium. In practice, therefore, 

 each individual specimen must, with our present knowledge, be judged on 

 its own merits, apart from all preconceived theories. Moreover, as the 

 ' Caunoporce ' and ' Biapora ' show many points of interest which are quite 

 independent of any hypothesis as to their actual nature, I shall, where 

 needful, describe and figure any noticeable features in connectioii with tbe 

 ' (?a««o/)ora-state ' of certain Stromatoporoids, irrespective of all theoret- 

 ical views as to the precise nature of this ' state.'" 



