Mr. J. E. Gray^s Outline of an Arrangement of Stony Corals. J21 



specimens which showed any variation or peculiarity of structure. 

 Being now called, by the increased space which I have at my dis- 

 posal, to re-arrange the collection, I intend in the following paper 

 to embody the result of my experience in the study of these in- 

 teresting beings. 



Pallas divided the Madrepores into seven groups, according to 

 their general forms (Zooph. 275). Lamarck gave names to these 

 groups, and extended their number, taking for the characters of 

 his genera the form of the cell, the position of the mouth of the 

 cell, and the distribution of the cells with regard to each other in 

 the mass, and also if they were distributed on both or confined 

 to the upper surface of the mass, and if the mass was fixed or 

 free. 



Forskal figured the animal of several species, Savigny in the 

 great work on Egypt figured another, and arranged them with the 

 harder Actinice ; and subsequently Lesueur in three papers pub- 

 lished in the Memoires of the Museum and Philadelphia Journal, 

 figured the animal of some other genera. Blainville with these 

 materials and with the original drawing made by MM. Quoy and 

 Gaimard in their ' Circumnavigation,^ in his article Zoophytes in 

 the ^ Dictionnaire des Sciences Naturelles^ (afterwards published 

 separately as a Manual) attempted to characterize the genera by 

 the conjoint consideration of the animal and its coral, paying 

 more attention to the form of the cells than to the form of the 

 coral and the distribution of the cells in the mass, and certainly 

 he succeeded in much improving Lamarck^s arrangement ; and 

 having Lamarck's original specimens within reach, he has referred 

 them to their proper genera according to his view, and produced 

 one of the best works on these animals which has yet appeared. 

 Unfortunately, like Lamarck, having only isolated specimens, and 

 often only fragments to examine, M. de Blainville has placed too 

 much reliance on the general form of the corals : thus he divides 

 his genus Gemmipora into arborescent, explaniform and crusti- 

 form ; the Montipora into crateriform and explaniform species ; 

 the Porites into incrusting, conglomerate and branching species ; 

 when the same species of these genera may be found in each of 

 these forms, and the species founded on these characters depend 

 only on some accidental and often local peculiarity of the speci- 

 mens, or may even have been broken from the same specimen. 



M. Ehrenberg in 1834 proposed an arrangement of Zoophytes, 

 which, though it has much the external appearance of novelty, 

 made very little addition to the real knowledge of the stony 

 corals ; for his generic characters differ very little from those 

 given by Lamarck and Dc Blainville, though they are expressed 

 in a very difi'crent manner, and made chiefly to depend on 

 the mode in which the buds are developed ; and as this circum- 



Ann. ^ Mag. N. Hist, Vol.xix. 9 



