48 



THE GENUS MONTICULIPORA. 



fig. \d), many of the spines become so far aborted that their 

 central cavities are no longfer to be detected, while others 

 attain their full development. These aborted " spiniform 

 corallites " appear to be in general what Dybowski has called 

 '* Wandstrange," though he has apparently included other 

 structures as well under this name. As these aborted spines 

 appear, however, in forms of very different affinities (such as 

 M. tumida, Phill., and AL Girvanensis, Nich.), it seems clear 

 that they are of no classificatory weight, whatever view we 

 may take as to their real nature. 



Lastly, if we admit the probable correctness of the views 

 here advanced, we have a very interesting analogy established 

 between certain forms of Monticulipora and some of the spe- 

 cies of Stenopora, Lonsd., in which structures of a precisely 

 similar nature occur. Thus, if we examine a tangential section 

 of Stenopora Tasmattiensis, Lonsd., taken just below the sur- 

 face (fig. 6), we see that the surface-spines are continued in- 



Fig. 6. — A, Vertical section of a few of the corallites of Stenopora Tasmaniensis, Lonsd., in 

 the final portion of their course, enlarged twenty times, showing the annular thickenings 

 of the tubes and the remote tabula ; B, Tangential section of the same, taken just below 

 the surface, similarly enlarged, showing the transversely divided spiniform corallites be- 

 tween the ordinary tubes. Carboniferous, Australia. 



wards precisely as they are in Monticulipora monili/oi'mis and 

 allied types, while they are similarly composed of concentric- 



