22 Trof. J. W. Gregory on the 



■whose opinion was no doubt formed independent!}', as he does 

 not refer to Prof. Heilprin's paper. In Brook's great mono- 

 grapli of the genus Madrepora lie not only merged Lamarck's 

 tliree West- Indian species, but adopted for them Linnieus's 

 name of vniricata. 



During a recent visit to the West Indies I have liad the 

 opportunity of studying the three forms of ^^adrepora on the 

 reefs, and have been led to revert to the Lamarckian arrange- 

 ment. As in 1895* I accepted Brook's proposals, it may be 

 advisable to state the reasons for my change of opinion. 



It will be convenient first to consider whether the West- 

 Indian Madreporce are all to be included in a single species. 

 Brook supported this idea by two lines of evidence : — 1st, the 

 distribution of the corals on the reefs ; 2nd, the existence of a 

 series of specimens having characters intermediate between 

 those of Lamarck's species. 



Habit and Environment. 



The first argument was based on statements that Brook 

 attributed to Pourtalfes. Thus he says t that Pourtalfes has 

 " hinted that the three species of Lamarck may prove to be 

 variations of one species, dependent on environment for their 

 precise habit." But this is not quite a correct account of 

 Pourtal^s's opinion. The only reference to Pourtal^s which 

 Brook includes in his synonymy is to the memoir on the 

 *' Deep-sea Corals." Therein Pourtalfes \ does hint that possibly 

 M. cervicornis and M. prolifera may be specifically identical ; 

 but he makes no suggestion that M. palmata should be 

 united with them. He even comes finally to the conclusion 

 that M. cervicornis and M. prolifera may be conveniently 

 kept apart. The passage referred to is as follows : — " Some 

 specimens partake so much of the characters of both this 

 [i. e. M. prolifera] and the preceding species [J/, cervicornis] 

 as to shake the belief in their specific difference. IStill the 

 greater number of specimens examined are readily distin- 

 guished, more perhaps by their habitus than by the more 

 minute characters of the calicles." 



Pourtales's conclusion seems to me sound. Specimens of 

 M. pjTohfera and M. cervico'rnis are distinguishable without 



* J. "^^^ Gregon*, " Contributions to the ]*aL'ecntology and Physical 

 Geography of the ^V est Indies," Quart. Journ. Geol. See. vol. li. (]895) 

 p. 282. 



t Brook, op. cit. p. 18. 



\ L. F. de Pourtales, " Deep-sea Coral.«,' 111. Cat. Mus. Comp. Zool. 

 no. iv. 1871, p. 84. 



