TUEBINARIA. 5 



His 49th genus is Turbinaria of Okeii, which comprised the " Explanaria, Lamk. ex parte, 

 and Gemmipora, Blainville." And his 50th genus is Explanaria, Lamk. 



The guiding principle in this rearrangement was clearly to keep the genus Turbinaria 

 for the smaller, more regularly cup-shaped coralla, wliile Explanaria contained the larger 

 membranous corals, in which, if any of them were TurUnaricc, the cup shape was obscured or 

 obliterated. Tliis can be gathered from his definitions. In the former case the corallum is 

 described as stalked, in the latter there is said to be no stalk. 



In his genus Turbinaria he has three species : T. cupula, T. peltata, and T. microstoma. 

 How completely he was in the dark as to the transitory nature of the cup form, may be 

 gathered from the fact that a specimen (or specimens) of his T. cupnda, showing folding of the 

 margin, became a variety, T. piUcatula. 



Ehrenberg failed to identify any of his specimens with the T. crater of Pallas; and 

 T. cincrasccns lie referred to the genus Explanaria. Dana has suggested that Ehrenberg's 

 T. eujmla is the same as his own (Esper's) 2Kltata, and Ehrenberg's p)dtuta is the same as 

 Dana's patula ; this suggestion seems to have been generally adopted. But, in view of the 

 fact that the species of Turbinaria are far more numerous than Dana was at all aware of, 

 it is quite as probable that Ehrenberg's Eed Sea Turbinarians were distinct. 



Of the seven species of his Explanaria, only one appears to be a true Turbinarian, viz. 

 T. cincrasccns. This, from the description, appears to be the true T. raescnterina. 



With regard to his system of classification of corals, Ehrenberg lays it down as a 

 principle that, the coraUum being a product of the fission, budding, or stolon-formation of 

 individual coral animals, the method of reproduction is of prime importance. 



Accordmgly, in his definitions of the genera, he describes the various methods of budding 

 or stolon-formation in each case. We have, therefore, descriptions of the budding of his 

 genus Tu7-Mnaria ( = jo\ing cup-shaped Turbinarians) and of his genus Explanaria ( = o\dv\ 

 specimens in which, when Turbinarians, the cup is obscured). 



His account of the budding in " Turbinaria " is somewhat different to that already 

 given by Oken. It is not easy now to understand exactly what he meant. The description 

 runs as follows : " TJic stars send out stolons lateralhj in all directions. There is no ordinary 

 budding except ahwrmalli/. The stolons, joined together, rise freehj from the siibstratiim. TJiere 

 is a common base, forming a stalk; the form is aceordinghj circidar, and often cup-shaped."* 

 And further on he adds, that " the Turbinarim are not neccssanly concave." 



It is clear, from this description, that Ehrenberg had not recognised the true method 

 of budding peculiar to the genus. That he did not mean the axial polyps in the stalks 

 of different cups by "the stars which send out the stolons" follows from his repeating the 

 same words in his description of the genus " Explanaiia;' which, according to him, has no 



* The Latm, of which the above is a free rendering, is as follows: " Slcllis proliferis, undigue 

 a latere (ohluiue) stoloniferis, nee mere gemmasccnlibus nisi monslrmse, nee didduis, stolonihtis conjunciim 

 libere ascendent ibus, basi communi, in slipitem pallia semper obductum data, stirpe extus sterili (hinc orbicu- 

 lares et sa;pe cujyulifoj-mcsj." 



