372 PROCEJEDINGS OF THE NATIONAL MUSEUM. vol. xxvm. 



OBJECT OF THIS WORK. 



1 therefon^ decided to inuko a compilation of the original diagnoses 

 of the various genera, to tix tiie type-species wherever possil)h% to sup- 

 plement the original diagnoses by subsequent observations based pri- 

 marily upon the type-species, to make a tentative classification, and, 

 where the information concerning a genus or a grou}) of genera is not 

 sufiicient for purposes of classification, to point out what should be done 

 in order to make the genera recognizable. After having given the 

 original diagnosis of a genus, designated its type-species, and stated 

 its distribution, under "remarks" a historic sketch of the increase in 

 knowledge concerning it and critical notes on it are given. The method 

 is cumbersome, but, as this paper is pi-imarily a critical review of lit- 

 erature, it seems to me to be the correct one. 



THE NECESSITY FOR THE DESIGNATION OF TYPE-SPECIES. 



Most modern systematic biologists will probably ])e surprised to see 

 stated in a heading a principle that is all but universally recognized. 

 Several of the older zoophj'tologists recognized the necessity/ of type- 

 species for genera. Leuckart in 1841 did, Milne Edwards and Haime 

 invariably designated a type-species, and Laube erected monotypic 

 genera. Many of the later workers have not done this, making :.t 

 extremely difficult to tind out precisely how the genera should be 

 defined. Investigations subsequent to the founding of a genus have 

 frequently been based on some other species than the geno-type, and 

 often not even the name of the species investigated is given. These 

 studies have not infrequently been used in redefining a genus, giving 

 rise to extreme confusion. The failure to base redefinitions of genera 

 primarily upon type-species and the failure to give the names of the 

 species upon which studies were based have invalidated some of the 

 most painstaking work that has been done on corals. 



The genus ThamnaMerla^' Le Sauvage furnishes an excellent illus- 

 tration. This genus was estal)lished for lliariDiasterki laiiKnirouxi Le 

 Sauvage = % A^trea dtiidrolded Lamouroux. ^' The spelling of the 

 name was subsecjuently changed to TJiamnastrea^ and is now usually 

 spelled Th((ninasti';v((. Pratz, in his Lleber die verwandschaftlichen 

 Berziehungen einiger Korallengattungen,'' gives an elaborate descrip- 

 tion of the finer sti'ucture of a coral referred b>' him to TJiamnaxtrsea^ 

 but he does not give the name of the species. Duncan, in his Revi- 

 sion of the Families and Genera, utilized Pratz's work. Ogilvie, 

 in her Korallen der Stramberger Schichten, did the same. Kob}' 



a Mem. Soc. d'llist. nat., Paris, I, 1822, p. 243. 



^ Expos, method. Genres Polyp., 1821, p. 85, pi. lxxviii, lig. 6. 



ePalaHmtographiea, XXIX, 18S2, i)p. 92-98. 



