BRYOZOA. 683 



The erection of a new family for Crisinella may be justifiable 

 in a work of that kind ; but not so the ENALLOPORID.E, under 

 which he ranges Diploclema, Enallopora and Protocrisina, since 

 the EXTALOPHORID.E will include these genera without any ex- 

 tension of its usually accredited limits. We must protest also 

 against the use of d'Orbigny's Enallopora instead of our Mito- 

 clema. Ennllopora was founded upon Hall's figures and des- 

 cription of Gorgonia (?) perantiqua (Pal. X. Y. Vol. I, 1847.) Mr. 

 Miller gives the following free translation of d'Orbigny's des- 

 cription (Prodr: d. Pal. T. 1, p. 22, 1850.) "Small bifurcating 

 branches, without connecting bars; cell-mouths prominent on 

 each side, opening laterally and alternately." How can this 

 description be made to include Mitoclema cinetosum, in which 

 cylindrical stems are encircled by transverse rows of zooecial 

 apertures as in Spiropora and Enthalophora! Nor are we 

 acquainted with any bryozoan from the Trenton rocks having 

 two rows of alternately arranged and outwardly projecting cell- 

 apertures. The species which we originally identified with Hall's 

 G. (?) perantiqua (Jour. Cin. Soc. Xat. Hist. Vol. V, p. 159,) 

 since it was found to agTee neither with the description nor 

 with the figures given by Hall of that species, is now described 

 as new and made the type of the new genus Diploclema, a sub- 

 sequent and more careful examination having developed that 

 we were wrong in uniting the species with Mitoclema* We 

 have also become convinced that Hall's work on his Gorgonia 

 (?) perantiqua is faulty and that Enallopora rests upon char- 

 acters that are hypothetical and with no existence in nature. 

 If this view is right, then Enallopora cannot stand, since it 

 fails to fulfill the first and most important rule of nomenclature 

 in this that the description is not sufficient for the identification 

 of the organism named. And there is no rule known to us per- 

 mitting the retention of a genus founded upon imaginary char- 

 acters. 



His FEXESTELLID.E embraces all the genera placed there by us 

 save Thamniscus. D'Orbigny's very doubtful Reteporina, and 



* For further remarks upon this subject see note under Protocrisina eiigua (p. 405} 

 which is another of the forms that have been identified with Hall's species. 



