356 Linnaean Society. 



extension of the interior parts is upwards (the natural direction of 

 growth), while the enlargement of the seeds in the lower half tends 

 to press back the parts of the lower hemisphere, that uniform and 

 regular pressure will resolve a nearly spherical capsule into two 

 equal hemispheres. This remark he applies to Centunculus also, but 

 confesses himself at a loss to give any reason why the opening of 

 Trientalis, which depends on the same general causes, should be ir- 

 regular. For the separation of the lid of the capsule in Hyoscyamus 

 he accounts by the contraction and rigidity of the throat of the calyx 

 exercising a gradually increasing pressure around the upper part of 

 the capsule, and thus causing its separation by the first of the ge- 

 neral principles laid down. 



The author then proceeds to the case of Lecythis, which he thinks 

 is to be explained by the third of his general principles. In illus- 

 tration of his principle he refers to a monstrosity, of the common 

 Tulip, described and exhibited by himself some years ago at a meet- 

 ing of the British Association. In this monstrosity, the upper leaf, 

 being unusually developed, has cohered by its edges so firmly as to 

 imprison the flower, and this constraint occurring at a period when 

 the stalk was increasing in length, and previous to any consider- 

 able enlargement of the flower-bud, the force applied was chiefly 

 vertical, and has carried off the upper part of the leaf in the form of 

 a calyptra, leaving the lower part in the shape of a cup, from the 

 centre of which the stem appears to rise. The separation of the lid 

 of the capsule of Lecythis he believes to be effected in an analogous 

 manner ; the septa which form the two or four cells into which the 

 fruit is divided meet in a thickened axis, and the outer part of the 

 fruit becoming (partly from its natural texture and partly from the 

 adherence of the torus and calyx) hard, solid and fully grown, while 

 the axis continues slowly to extend, and thus to press upwards that 

 portion of the capsule which rests upon it, causes that portion first 

 to become slightly prominent, and finally by a strain upon the vessels 

 of that particular part to fall off in the shape of a lid. In Couroupita 

 the pressure is sufficient to mark the surface of the fruit with a pro- 

 minence, but from the partitions giving way early, and from the 

 abundant juices produced m the interior, there has not been, he con- 

 ceives, sufficient pressure to occasion disruption. In all the species 

 of Lecythis, he observes, the extent of the loose cover corresponds 

 with the extent of the axis, and what remains of the latter continues 

 attached to it. 



As regards lomentaceous fruits in general, the author believes that 

 the intervals between the seeds being sufficient to admit of the sides 

 of the fruit cohering (which is promoted in particular instances by 

 special causes), the swelling of the seeds afterwards stretches the 

 parts over them in a degree which this coherence prevents from 

 being equally distributed, drags the tissue forcibly from the junc- 

 tures which are fixed points, and thus there being a strain in each 

 direction from the middle line of the juncture, the contraction of 

 drying during the ripening of the fruit effects the separation. 



Finally the author refers to the horizontal separations in the cap- 



