Miscellaneous. 137 



the order of the Active Lemur, resembling in the main a small squir- 

 rel, but of a lighter hazel, with very large eyes, and the fore feet 

 very much like the human hand, except that there was a protube- 

 rance on the ball of each finger and toe ; also the Thumbless Monkey. 



Yours very sincerely, 



T. Perronet Thompson. 



On the Nectariferous Glands of Leaves, and on some Saccharine Se- 

 cretions. By M. Unger. 



M. Unger was led to this investigation by his observing on an 

 acacia, in the spring of 1843, that whilst the plant was in flower, a 

 saccharine and transparent liquid flowed from its phyllodia in nu- 

 merous drops. In 1844 he observed a similar phenomenon on other 

 species of the same genus, but not upon all. 



The attention of this German naturalist was particularly directed 

 to the species in which the secretion is the most abundant, the Acacia 

 longifolia. 



At the base of the lamina of the leaf or of the phyllode of this 

 plant, and at its upper margin, a small impression is remarked in the 

 form of a point, which is the orifice of the excretory canal of a cavity 

 existing in the substance of the organ. This cavity is not hollowed 

 in the ordinary parenchyma, but it is surrounded entirely by peculiar 

 cells with small and thin walls, the whole constituting a sort of 

 glandular apparatus, in the form of a haricot bean, voluminous, and 

 attaining as much as a third of the volume of the phyllode. It is 

 surrounded by several vascular bundles, and has direct relations with 

 four of them. 



The cells which form the gland contain no solid matter ; but those 

 which surround this apparatus contain granules of starch which be- 

 come more numerous and larger in proportion to their distance. 

 The liquid which fills them is turbid, which shows its state of con- 

 centration. On examining it with the aid of some re-agents, M. 

 Unger was led to admit that it contains, besides the sugar, a second 

 substance, gum or vegetable mucilage. This organization recalls 

 what Schlechtendal has described on the leaves of the Viburnum 

 Tinus and the Clerodendron fragrans. 



The author deduces the following results from his observations : — 



1. The nectariferous glands of the leaves possess, with respect 

 to their essential structure, a great analogy with one another. 



2. The production of the sugar is effected in all in the same 

 manner. 



In the interior of the glands of the Acacia longifolia, and toward 

 their deferent canal, M. Unger has traced the existence of several 

 small brown bodies, in the form of articulated tubes, which he thinks 

 may be regarded with some reason as belonging to the Cladosporium 

 fumago, Linck, a polymorphous fungus which was abundant in the 

 ground where this acacia was found. 



To M. Unger's memoir is added an appendix, the object of which 

 is certain abnormal saccharine secretions. Among these secretions, 



Ann. §• Mag. N. Hist. Vol. xviii. L 



