12 THE GENUS MONTICULIPORA. 



eating increments of growth. The two species described 

 under this head are D. detritus, Eichw. (which Eichwald 

 expHcitly states to be the type of the genus— /(?<:. cit., p. 487), 

 and D.fastigiatns, Eichw. The two species in question are 

 quite indeterminable, so far as Eichwald's descriptions and 

 figures would serve this purpose.^ The figures which are 

 o-iven of these forms would seem to be inverted; but this may 

 not really be the case. There is nothing, however, either in 

 the figures or text, which would enable us to decide whether 

 these types are referable to Monticulipora, or Fistiilipora, or 

 Prasopora, or to some other Monticuliporoid type. So far as 

 the structural characters of the genus Dianulitcs are concerned, 

 the presence of a thick lateral epitheca, though strongly insist- 

 ed upon by Eichwald in his remarks upon the genus, cannot 

 be regarded as of any special importance ; and the only funda- 

 mental character mentioned is, that the tabulate corallites are 

 surrounded by a " spongy coenenchyniar This character, being 

 common to many Monticuliporoids — since the "interstitial 

 tubes" of these are the " coenenchyma " of the older writers — 

 cannot, however, constitute alone a basis for generic separation. 

 I shall subsequently give my reasons for rejecting Dian- 

 iUites, Eichw. (emend. Dybowski), these reasons being partly 

 that I do not regard the genus (as redefined) as a natural divi- 

 sion, and partly that I do not admit the propriety of endeav- 

 ourino- to restore old generic names which were originally 

 defined in an absolutely worthless manner.- In the meanwhile, 



1 Dybowski (Die Cha;tetiden, pp. 20, 21) states that D. detritus and D. fastigi- 

 atus are merely different conditions of tlie same species, for which he retains the 

 latter name; and he further considers Clicetetes Fa/ideri, E. and H., to be a syno- 

 nym of this. For my own part, I cannot recognise the reasonableness of setting 

 aside a (by comparison) well-characterised type, such as the C. Panderi of Ed- 

 wards and Haime, in favour of a type so defined originally as to be beyond pos- 

 sible recognition — even though an observer, fortunate enough to have access to the 

 original specimens, should ultimately be able to show that these possess characters 

 entitling them to generic or specific distinction. 



2 I entirely endorse, on the other hand, the proposed rule of the Committee of 

 the International Geological Congress on Pateontological Nomenclature, that " le 

 nom attribue a chaque genre et a chaque espece est celui sous lequel ils ont ete 

 le plus anciennement designes, a la condition que ce nom ait etc public ct claire- 

 mcnt deJiniP The Eichvvaldian genera of Monticuliporoids do not even approxi- 



