Mr. J. Miers on the genus Brachistus. 261 



^' stones are only swallowed by frugivorous birds, which require 

 them to triturate their food, and are never found in the gizzards 

 of the Raptores." Hence it was argued, that the Dodo, which is 

 known to have had stones in its stomach, could have no affinity to 

 Raptorial birds. Dr. G. Dickie of Aberdeen has however called 

 my attention to a passage in Sir J. C. Ross's Antarctic Expe- 

 dition, which shows that the above generalization, though un- 

 doubtedly true in general, admits, like all rules, of an exception. 

 It is there mentioned (voL ii. p. 159) that stones were usually 

 found in the stomachs of the Aptenodytes Forsteri, to the amount 

 of two to twenty lbs. weight. This is certainly a remarkable 

 fact in the case of a piscivorous bird, and indicates some pecu- 

 liarity in its habits which it would be desirable to clear up. Do 

 any of the fucivorous Fish swallow pebbles to help digestion, 

 and can the Penguin have thus acquired these foreign matters at 

 second hand ? But whatever be the cause of this habit in the 

 Penguin, it does not affect the argument as to the remoteness of 

 the Dodo from the Raptorial birds. 



XXXIl. — Contributions to the Botany of South America. 

 By John Mters, Esq., F.R.S., F.L.S. 



[Continued from p. 146.] 



Brachistus. 



A PARTICULAR group of plants has been before alluded to under 

 this name {ante, p. 144), most of which have been referred to 

 Witheringia by Prof. Kunth, and from which genus I have shown 

 that they differ by having a campanular calyx generally with an 

 almost entire margin, which does not enlarge with the fruit, by 

 a much smaller berry and other characters. They are also di- 

 stinct from Acnistus by the calyx being generally entire on the 

 margin, rarely 5 -toothed, and not having the five strong prominent 

 nervures which give to the calyx of the latter genus the appear- 

 ance of an almost pentangular tube : they differ also in the much 

 shorter tube of the corolla, a more rotate border, more dilated 

 stamens arising from a triangular expansion at the base, as in 

 Hehecladus and Saracha ; their flowers are considerably less in 

 size, and they have smaller berries, which exhibit a very thin 

 membranaceous dissepiment, not thickened in the middle by the 

 confluence of the placentae, as in Witheringia, Acnistus, lochroma, 

 Saracha, &c. ; the placentse on the contrary, originating from a 

 central line in the middle of the dissepiment, are thin and 

 slender, projecting for a short distance at right angles into the 

 cavity of the cell, and then become furcated, continuing mem- 



