2 BRITISH STROMATOPOROIDS. 



genus could not properly be referred to the true Corals. The first species 

 described by Goldfuss under the head of Stromatopora — and the species therefore 

 which constitutes the type of the genus — is 8. concentrica, a name which has 

 obtained universal currency, and which has been employed by palaeontologists for 

 a large number of different Stromatoporoids from various parts of the Silurian and 

 Devonian formations. As 8. concentrica is the type of the genus Stromatopora, it 

 becomes a matter of the greatest importance to ascertain precisely its characters 

 and its minute structure, and with this end in view I have made a careful exami- 

 nation of the original specimens of this, and of the other species of Stromatoporoids 

 described by Goldfuss, all of which are preserved in the Museum of the University 

 of Bonn. My friend, Prof. Schliiter, has also had the kindness to have prepared 

 for me thin sections of the original specimen of S. concentrica, Goldf ., and of some 

 others of the Goldfussian types, such sections not having been previously in 

 existence. It may be as well therefore that I should indicate here the general 

 results that I have arrived at as to the characters and structure of the different 

 forms of the Stromatoporoids which Goldfuss has described and figured in the 

 ' Petrefacta.' 



(1) Stromatopora concentrica, Goldf. — The type-specimen of this form, as 

 figured by Goldfuss (' Petref. Germ.,' Taf. vi, fig. 5), is preserved in the Bonn 

 Museum, and has the form of a large mass, composed of numerous thick concentric 

 strata, separated by narrow interspaces which are more or less largely filled with 

 oxide of iron. The concentric strata (" latilaminaa ") are from 1\ to 3 mm. in 

 thickness, and are more or less undulated. The general texture of the fossil is so 

 dense that no clear idea can be obtained as to the minute structure of the skeleton 

 by the use of a hand-lens. Besides the figured specimen, the Bonn Museum 

 possesses another example of 8. concentrica of precisely the same general aspect, 

 the two having very probably originally formed part of one fossil. 1 A microscopic 

 examination of thin sections of 8. concentrica, Goldf., shows that the skeleton is 

 essentially a complex network of anastomosing calcareous fibres, so disposed as to 

 enclose correspondingly complex anastomosing canals. In the main, two sets of 

 fibres may be distinguished, though the two are so united as to form a continuous 

 reticulation. The fibres of one series are vertical, and each of the successive 

 concentric strata (" latilaminas ") of which the skeleton is composed is traversed 

 by such fibres running continuously from the under to the upper surface. The 

 fibres of the other series are tangential to the surface, or at right angles to the 

 vertical fibres, and are very irregular. There are, also, two corresponding series 



1 I may mention that at one locality near Gerolstein, in the Eifel, I have collected a number of 

 specimens which in general characters, and in their mode of preservation, are absolutely undistinguish- 

 able from the above-mentioned originals of Goldfuss, and I have little doubt that Goldfuss collected 

 his specimens from the same locality. 



