S UB- GENUS MONO TR YPA. 



175 



Obs. — Examples of this species are of common occurrence in 

 the Devonian Limestone of Gerolstein, and are so entirely 

 similar in form (fig-. 34, a) to the Lower Silurian I\I. pctropoli- 



Fig. 34. — Alonticiilipora M'intcri, Nich., Devonian, Gerolstein, Eifel. A, A specimen, of the 

 natural size, viewed in profile; B, Base of the same specimen, of the natural size; C, 

 Part of a tangential section of the same, enlarged eighteen times ; D, Part of a vertical 

 section, showing the remote tabulre, similarly enlarged. 



tana, Panel, that a merely macroscopic examination would 

 almost certainly have led to their being identified with the 

 latter form. A microscopic examination, however, shows that 

 their structure is that of Monotrypa, and not that of Diplotrypa, 

 all the tubes alike being essentially similar in their internal 

 characters. Tangential sections (fig. 34, c) show that the tubes 

 are essentially uniform in size, a few slightly larger ones form- 

 ing scattered clusters, while such intercalated small ones as 

 are present are obviously merely young corallites. All the 

 tubes also are bounded by very delicate walls, and are regular, 

 angular, and prismatic. Vertical sections (fig. 34, d) show a 

 complete identity in structure in all the corallites, the tabuke 

 being complete and remote, and sometimes placed at corre- 

 sponding levels in many of the tubes. 



Recently, Dr Daniel CEhlert, of Laval, has been good 

 enough to send me a number of specimens, from the Inferior 

 Devonian deposits of La Baconnicre, Laval, which agree 

 precisely both in their external characters and their minute 

 structure with examples of I\I. Wiiitcri from the Eifel. 



With regard to the Eifel specimens, Dr Steinmann, whose 



