4 RECENT MADREPORARIA OF THF HAWAIIAN ISLANDS AND LAYSAN. 



The use of Leptmirm as a jreims iiaine is coiitiniu'd, iiltliouj^h Mr. Stanley 

 Gardiner" thinks that it should be referred to the syiionyin.v of (>i'l>!relhi. A certain 

 niiMil>er or a <,nT)ui) of orhicoUan corals are ciiaiacliMizcd by a compact, costal 

 exothoca, to which the name Z.y^Aw/'m? was applied. 1 tiiul the name convenient, 

 but think that it probably should be reduced to sidjociicric rank. 



THE SPECIES PROBI-EM IN CORALS. 



The species problem, as a pn)l)lcui of uciinal l)i()lo,<>y, is still a subject of 

 vi<i;orous debate and wide divergence of opinions amono l)i(ll.)^■ists. Some contend 

 that species originate by the ji^radual accunuilation of small ditferences, the diver- 

 oence of the daiii;liter from the parent species beiny by iiitinitesimals;* others, 

 de X'ries and his followers, maintain that new species do not owe their origin to 

 •such infmitesimal divergence, but suddenly spring into existence, differing at the 

 beginning by distinct lacuiue from the parent species. Some admit that new species 

 may come into existence by either process. I have put myself on record as believing 

 that the data accumulated to the presiMit time ari^ not sufficient to warrant our form- 

 ing a positive conclusion.' 



Since the problem as to how new species originate has not been satisfactorily 

 solved, a logically grounded definition of l)iological species is at present impossible. 

 The following ilctinition is assumed: A species is a group of individuah connected 

 among the)n.ielves hy intergrading c/iaracters and separated hi/ distinct lacunx from 

 all other individuals or groups if individuals. The lucunaj, or discontinuity of 

 chai'acters, would be ac(;ounted for by the infinitesimal theory on the assumption 

 tliaf the intergrades, assumi^d once to have existed, iiave become extinct: the 

 mutation theory assumes that they never existed. Whichever theory may lie 

 correct, the recognition and definition of species is based on the study of variation. 



\'ariation in corals is, we know, great and complex. If we knew its limits, we 

 •slioidd know the limits of the different species. Bernai'd, in cataloguing the 

 Perforate Corals in the British Museum (Natural History), experienced so much 

 difliculty in d(>fining them from the collections at his disposal that he decided 

 to abandon the Linnajan system of nomenclature, and to use in his catalogues a 

 geographical numlier system. 



This sy.stem has been expounded in four different publications.'' The scheme 

 suggested can be briefly outlined as follows: The specimens belonging to a given 

 genus from a specific locality or an area are divided into as manj' forms as possible, 

 as, for example, he recognizes 9 different kinds of P(yrites from the Hawaiian Islands. 



"Madreporaria, Fauna and (ieosraphy of the Maldive and Laccadive Archipelagoes, II, p. 774. 



'' C. II. MiTi-iani, Ii* Mutation a Factor in tlie Kvohition of tlie I Uglier Vertebrates ? Science, n. s., 

 XXIII, l!)Ot;, pp. 241-247. 



"•The Work of Hugo deVries and its Importance in the Studv of I'rcjblems of Evolution. Science, 

 n. s., XXIII, 1906, pp. 681-691. 



rfA paper read before the Linnican Society of London, February 7, 1901, pp. 10, 11. 



Nonienclatur und Entwiclielungslehre, International Zool. Cougr., Berlin, 1901, pp. 891-S96. 



The Unit of Classification for Systematic Biology, Proceedings, (Jauibridge Philosophical Society, 

 XI, 1901, pp. 268-280. 



The Genus Goniopora, Cat. Madrep.. Brit. Mus. (Natural History), IV, pp. 34,3.5. 



