23 BRITISH STROM ATOPOROIDS. 



which is, unfortunately, insufficiently illustrated, but which is otherwise a 

 very valuable and important contribution to the subject ; so I need here only 

 indicate its general scope. Commencing with a historical summary, the author 

 next gives a detailed account of the general structure of the skeleton in the Stro- 

 matoporoids. He describes this structure as consisting of a series of horizontal 

 and vertical, or concentric and radial, elements ; and expresses the view that 

 Caunopora, Phill., is the only type of the Stromatoporoids in which the skeletal 

 elements are disposed indifferently, so as to give rise to a " curvilinear " or round- 

 meshed structure. The " radial pillars " he regards as invariably solid, and he 

 states that he has never observed them to open by apertures on the surface. The 

 pores in the concentric laminae are regarded as having served for the exit of poly- 

 pites ; and Carter's views as to the homology between the astrorhizce and the 

 coenosarcal canals of Hydractinia are accepted. The existence in some forms of 

 vertical wall-less tubes, which give off the astrorhizEe of successively superimposed 

 interlaminar spaces, is noted ; and it is rightly pointed out that these have nothing 

 to do with the walled tubes of Caunopora. The absence of such a central vertical 

 tube in the astrorhizas of various Stromatoporoids is further shown to be due to 

 the fact that in these forms the astrorhizaB of successive interlaminar spaces do 

 not lie above one another, or correspond in position. With regard to Caunopora, 

 Phill., Bargatzky considers that two distinct groups have been included under this 

 name. In one of these groups, the general skeleton has a " curvilinear " struc- 

 ture, and to such forms he would restrict the name Caunopora. In the other 

 group, the skeleton has a " rectilinear " structure (really only partially so), and for 

 forms of this type he proposes the new genus Diapora. As regards both Cauno- 

 pora and Diapora, Bargatzky concludes that the walled tubes are not foreign to 

 the organism in which they occur ; and he gives various detailed reasons for this 

 view. The genus Parallelopora, the characters of which I shall discuss subse- 

 quently, is founded by Bargatzky for some Stromatoporoids from the Devonian 

 Rocks of the Paffrath district. The next section of Dr. Bargatzky's memoir is 

 occupied with descriptions of the species of Stromatoporoids which occur in the 

 Devonian Rocks of the Rhenish region. Owing to the fact that he had not 

 examined thin sections of the original specimens bf Goldfuss, Bargatzky has fallen 

 into the same error as all who had preceded him with regard to Stromatopora 

 concentrica, Goldf. He selects, namely, for this classical species the common 

 Devonian Stromatoporoid with the "rectilinear" or " hexactinellid " structure, 

 that is to say, with continuous " radial pillars " and with periodically-developed 

 horizontal connecting-processes. I have examined his named specimens in the 

 Bonn Museum, and he has also been so good as to show me the specimens in his 

 own collection, so that I can speak positively on this point. As a matter of fact, 

 however, as previously pointed out, the true Stromatopora concentrica of Goldfuss 



