124 THE GENUS MONTICULIPORA. 



tuniida, it is impossible to assert positively that this apparently 

 well-marked variety may not be really merely founded upon 

 some particular part of the adult skeleton, as, for example^, the 

 young, actively growing branches. In the meanwhile, it will 

 be of advantage, considering its conspicuous differences, to 

 regard it as at least a variety of M. tuinida, and to give it 

 a distinct title in accordance with this view. 



There is no species of Monticiilipora which comes so near 

 in its characters to M. tumida, Phill., so far as I know, as to 

 demand any detailed comparison. At the same time, it Is not 

 unworthy of notice that in many of its minute structural feat- 

 ures M. tiLinida certainly presents a very curious resemblance 

 to certain species of the genus Stenopora, Lonsd. {iion M'Coy). 

 So far as our present knowledge extends, the only points 

 which would definitely separate 71/. iinnida, Phill., from Stcno- 

 pora are, that it certainly shows no traces of the peculiar mon- 

 iliform and periodic thickening of the walls of the corallites 

 which is characteristic of the latter genus, and that there is 

 no evidence as to the presence of mural pores. Till, however, 

 the very anomalous and remarkable characters of the genus 

 Stenopora, Lonsd., are completely elucidated — which will not 

 be the case until a large number of examples have been sub- 

 mitted to careful examination by modern methods — it would 

 be premature to attempt any definite conclusions as to the 

 real af^nities of M. tumida, Phill. 



Horizon and Locality. — Common in the Lower Carbonifer- 

 ous rocks of Great Britain generally. The specimens which 

 I have examined microscopically are from the Carboniferous 

 rocks of Redesdale, Northumberland, and Reagill, Westmor- 

 land. 



