58 



STANLEY SMITH. 



short, and the tabulae flat or concave. Lonsdale (op. clt.) 

 gave to the non-columate fasciculate forms of Lithostrotion 

 the generic name Diphyphyllum, and to the similar massive 

 types the name Stylastraea. The distinction was not 

 accepted as of generic value by Milne Edwards and Haime, 

 and with their view, I concur. It is true, that I have found 

 at some particular horizon or locality Diphyphyllum late- 

 septatum M'Ooy [= non-columate form of L. irregular e 

 (Phillips)] occurring in great abundance to the exclusion of 

 the columate form; but on the other hand, I have observed 

 both types of corallite present in the same corallum. 



Systematic Classification. 



Any classification of a coral genus based solely on the 

 skeleton is highly unsatisfactory, and is permissible only in 

 the case of fossil corals the soft parts of which are un- 

 known. The researches of Prof. George Matthai, 1 and other 

 workers have shown that the " hard parts" of recent corals 

 afford no safe basis upon which to erect species. 



Fossil "species" and "varieties" may have little bio- 

 logical value, and should, perhaps be merely regarded as 

 necessary labels indicative of a close community of char- 

 acters shared by members of such a "species" or "variety." 



I have pointed out elsewhere 2 in discussing the classifi- 

 cation of Rugose corals that " Inconsistency of detail but 

 conservation of the general plan, is the most characteristic 

 feature of the skeletal morphology of the Rugose genera, 

 especially in the more specialised genera, since complexity 

 of structure widens the scope of variation." 



Lithostrotion has a comparative simple structure, yet 

 within its limitations it presents a bewildering series of 



1 A Revision of the Recent Colonial Astraeidae possessing Distinct 

 Corallites. Trans. Linn. Soc, ser 2 (Zool.), Vol xvn, 1914. 



2 Q.J.G.S., Vol. lxxi, 1916, p. 237. 



