784 



orders of flowerless plants, as in the case of certain ferns, in which minute leaves oc- 

 casionally occupy the position of the sorus, or part appropriated to the organs of repro- 

 duction. Professor Liudley, in speaking of the mosses, suggests that the calyptra, the 

 operculum, and peristomium may be nothing more than modifications of leaves ; and 

 that even the theca itself may also be the distended apex of the stem. No specimens 

 of mosses, however, illustrating this identity of the organs of reproduction with those 

 of nutrition, appear to have been observed, until Mr. Quekett discovered some which 

 go far to prove that these minute organs are capable, under certain circumstances, of 

 being converted into leaves, thus leaving but little doubt that modifications of leaves 

 are here employed as in ferns and in the higher orders of plants, to constitute the parts 

 concerned in the duty of reproduction. 



The specimens were produced in the following manner. Having placed some 

 mosses, with the fructification in difTerent stages of development, in one of the close- 

 glazed cases introduced by Mr. Ward, the author found that one of them (Tortula 

 fallax), which, when it was placed in the box, exhibited every tendency to produce 

 fruit, after a time lost every appearance of fruit advancing to maturation, a small tuft 

 of leaves appearing in its place. Upon examining the plant under the microscope, it 

 was evident that it was furnished with the usual leaves at the base. The seta existed 

 of the usual brown colour, quite destitute of leaves; but in the place of the capsule, 

 there was a continued elongation of the seta, of a green colour, bearing several leaves, 

 which were also green, and varying in number from twelve to sixteen ; and the author 

 considers it probable, that the elements of the modified leaves, which otherwise would 

 have formed the capsule and peristome, had been so influenced and changed by the 

 heat and moisture of the situation in which they had been placed, as to bring them in- 

 to a state fitted apparently for the purposes of nutrition only, and not of reproduction. 

 This change he supposes to have been effected by the elongation of the columella, and 

 the consequent carrying up of those leaves whose apices would, in the natural state, 

 have formed the peiistome. This variation from the ordinaiy structure of the parts of 

 reproduction in a moss, appears, in his opinion, fully to bear out the observations of 

 Professor Lindley before referred to, as to the identity of the calyptra, the operculum 

 and the peristome with ordinary leaves : but it is not so clear that the theca is to be 

 considered as the hollowed out apex of the stem. On the contrary, Mr. Quekett's 

 opinion was, that it is formed by the united edges of the carpellary leaves ; and he 

 concluded by adducing some instances in other plants in corroboration of this sup- 

 position. 



Mr. Varley exhibited and described a new form of microscope, which was said to 

 possess all the contrivances found requisite for any instrument ; and that many of the 

 defects of other forms had been more or less obviated. The principal novelty in this 

 microscope was a stage composed of one plate, being made to move on the surface of 

 a fixed plate by means of a lever : this arrangement being admirably adapted to watch 

 the movements of living creatures when submitted to magnifying powers. To effect 

 this object, Mr. Varley had the moveable plate connected with the fixed one by guides 

 furnished with ball and socket joints, which allowed it a perfect freedom of motion in 

 all directions, of a smooth and uniform character. Considerable ingenuity was dis- 

 played in the several contrivances of this microscope, which was capable of having Mr. 

 Varley's Graphic Telescope applied, for the drawing of objects in the field of the mi- 

 croscope. — /. W. 



