n MADREPOKARIA. 



stalk, and hence would have no axial polyp. In this respect Oken, whose comparison of the 

 arrangement of the polyps of Turbinaria to the inflorescence of an umbelliferous plant 

 suggests an axial polyp, came nearer the truth. Ehrenberg's statement that there is no 

 ordinary budding except abnormally is meant especially to emphasise the fact that the polyps 

 reproduce by " stolon-formation." This erroneous description of the method of budding has 

 been repeated by subsequent observers, and was only recently corrected by the present writer. 

 It cannot, however, detract from the honour due to this great naturalist for insisting upon 

 gi\ang to the method of reproduction its true value in the classification of the Corals. 



In 1848 appeared Dana's naagnificent work on the ' Zoophytes of the United States' 

 Exploring Expedition during the years 1838-42.' Dana proposed a classification of the 

 Zoophytes based upon the number and arrangement of the tentacles of the living animals, 

 and, like Ehrenberg, on the methods of reproduction. 



lu his first division, the Astrseacea, the gemmation is superior, and the oral discs divide. 

 In the second, Caryophyllacea, the gemmation is inferior. In the third, Madreporacea, the 

 gemmation is lateral. In the third family of the Caryophyllacea (in which the gemmation 

 is inferior) Dana placed the Gemmiporidaj, including two genera, Gemmipora and " Astrcco- 

 'pora.{T)" The genus Gemmipora is synonymous with Oken's Turlinaria, which name, in spite 

 of its priority, Dana rejected, because of its liability to be confused with Lamarck's genus 

 " TurUnalia " (= Turlinolia) ; and further, because Oken introduced his name " without 

 reference to the previously-formed genera of Lamarck." It may be remarked, however, that 

 Lamarck's gentis Explanaria first appeared in the second volume of his ' Histoire Naturelle des 

 Animaux sans Vertebres,' in 1816, the year after Oken's name appeared. The genus was not 

 made in Lamarck's earlier publications, referred to by Dana, viz. the ' Systeme des Animaux 

 sans Vertebres,' 1801, and the ' Extrait du Cours de Zoologie du Mus. d'Histoire Nat. des 

 Animaux sans Vert.,' 1812. 



Dana's genus contains seven species, of wliich four were already established — pdtata, 

 crater, cinerascens, and palifcra ; the three new ones were j)<-itula, frondcns and hrassica. 

 Lamarck's mesentcrina and Ehrenberg's cupula and microstoma are quoted as synonyms. 



We here find Dana recognising the relations of the individual corallites as one of the 

 leading principles of his classification. But his division of the species into three groups — 

 (1) glomerate ; (2) explanate, from a central pedicel ; (3) foliaceous, with the folia clustered — 

 shows that he did not recognise the fact that all Turbinaria are typically stalked at their 

 earliest stages, owing to their peculiar method of budding. The section which he gives of a 

 Gemmiporan (' Zoophytes,' fig. 27, p. 67) is only that of a portion of a frond, in which at first 

 sight the budding looks as if it were lateral-inferior, as he describes it. Dana thus prac- 

 tically repeated Ehrenberg's " stolon-formation." The error is very natural, inasmuch as it 

 is not easy to see how, without following the process of budding from the axial polyp in 

 the young stalked cup, any one could have recognised the true type of budding from the 

 section through a frond. 



One unfortunate result of this error was to compel Dana to divorce Gemmipora entirely 



