GENERAL HISTORY. 23 



having the priority (see Nicholson, Pal. Tab. Cor., p. 304). As 

 to the forms included by Dybowski under the head of Callo- 

 pora, Hall, the first is identified with the C. intminiforuiis of 

 Hall, and a number of figures illustrative of its structure are 

 given (PI. IV. figs. \-\k), from which it can be seen that at 

 least two distinct species have been placed under the same 

 name. Thus, it is certain that there can be no specific rela- 

 tionship between forms like those represented in PI. IV. figs. 

 \c and \b, where the large corallites are prismatic and have 

 complete horizontal tabulce, and such as figs, i/and i/^ of the 

 same plate, where the large corallites are circular and have 

 inco7nplete cxcentrically perforated tabtdce. The former are 

 certainly not Fistidiporcs, while the latter are undoubtedly 

 referable to Prasopora, Nich. and Eth. jun., and are nearly 

 allied to the form which I shall subsequently describe under 

 the name ol P. Schvynii, Nich. 



As regards the other species referred by Dybowski to Cal- 

 lopora, Hall, one — viz., C. maaUata, Dyb. — is an unquestion- 

 able member of the genus Fistidipora, M'Coy (and is there- 

 fore a Callopora) ; and C. hetcrosoleii, Keys., is probably sim- 

 ilarly referable to Fistulipora. On the other hand, C. pyrifor- 

 vds, Eichw., and C. ligid/onjus, Dyb., are almost certainly not 

 referable to Fistulipora, M'Coy, and the last of these would 

 seem to be a Diplotrypa. 



The fourth genus adopted by Dybowski is Trachypora, E. 

 and H., to which is referred the single species T. porosa, Dyb. 

 The form so named is an exceedingly remarkable one, and, 

 if its structure were sufficiently worked out, would probably 

 prove to be the type of a new genus. Be this as it may, it has 

 nothing whatever to do with the genus Trachypora, E. and H., 

 the latter being now known to belong to the Favositidce, and 

 to be entirely destitute of a " ccenenchyma " (see Pal. Tab. 

 Cor., p. 102). 



The fifth genus is Stellipora, Hall (Constcllaria, Dana), to 

 which are referred two new species — viz., S. Revalensis, Dyb., 

 and S, constellata, Dyb. With regard to these, it is sufficient 



