Ilydractinia, Parkoria, and Stromatopora. 67 



it sliced and polLslicd, has kindly Bubmittcd for my examina- 

 tion. 



AVhcther the tissue-fibre of this fossil was calcareous or not, 

 I am unable to decide, further tlian that, if rif^ht in identifyin*^ 

 the " branched, tortuous, dendriform fibre" on the surface of 

 the fossil with the cocnosarcal stolon-tubulation of Jlydractinia 

 ecliinataj the former also may have undergone the same 

 change — that is, from chitinc to carbonate of lime. 



I have stated that there are boss-like projections iiTCgularly 

 scattered over the surface of Loftusia persica, corresponding 

 with a wavy condition of the sjiiral lamina o])])osite them in 

 the section, and that they also bear branched lines i-unning 

 over their summits respectively, which look like traces of the 

 stellate systems seen in Bradya and Stromal opora (fig. 18, c) ; 

 but I have also added that most of these appear to be acci- 

 dental. How far the reason I have assigned for this may be 

 accepted, remains for future observation to detei-mine. 



It might be said that Bradya tergestina is a Stromatopora ; 

 but if so, Stromatopora is handed down to us in Parkeria ; for 

 the tissue-fibre and radiating tubes in Parkeria are, in a tan- 

 gential section, identical with those both of Bradya and Stro- 

 matopora. 



I regret that the fossil reached me after my plate of illus- 

 trations to this paper had been filled up ; but a diagram of the 

 tissue-fibre would only be a repetition of that which is given 

 of Parkeria in fig. 14, minus the incrustation ; and an almost 

 facsimile of the stellates may be seen in fig. 19, making 

 allowance for the larger size and lesser number of bosses in 

 Bradya tergestina ; while the branched fibre in prominent 

 relief on the surface is represented in the coenosarcal tubula- 

 tion of Ilydractinia echinata (fig. 3). 



D'Orbigny gives a figure, viz. Stellispongia variahilisj 

 very much in appearance like the above fossil, which is stated 

 to extend from the Trias (Salifdrien) to the Eocene (Suesso- 

 nien) strata inclusively (Cours ^l^jment. de Pal^ont. et d. Geo- 

 logic, t. i. p. 214, fig. 338). - 



Stromatopora. 



My friend !Mr. W. J. Sollas, who has for some time past 

 been directing his attention to the diflferent species of Stroma- 

 topora within his reach, and who has generously presented me 

 with some specimens, and brought to my notice others, had, 

 from the regular hexaetinellid structure of one in particular (to 

 which I shall return hereafter), been, like myself, inclined to 

 the idea that it was originally a Sponge. But when I learned 



5* 



