Microscopical Society. 2129 



pins to the diaphragm, so as to be parallel to it and about one-eighth of an inch dis- 

 tant from, it, with the flat side towards the eye-glass. Two pieces of metal, about 

 a quarter of an inch wide, must also be fixed to the disc, vertical to it and at right an- 

 gles to the slots, for the screws to work in. The calliper points are to be placed across 

 the slots, so that they may project half-way over the central aperture, and are to be 

 attached to small metal springs under the disc, by means of screws or rivets, so as to 

 allow of lateral motion from oue end of the slots to the other : these springs keep the 

 points always in focus. Two screws with milled heads work through holes in the ver- 

 tical pieces attached to the disc, and give motion to the points, and a helix of wire is 

 placed round the screws to steady the motion. Mr. Shadbolt described two other mo- 

 difications of this construction, the principle remaining the same. He concluded with 

 some remarks on the mode of expressing the value of the measure of au object, recom- 

 mending the uniform adoption of the decimal notation in preference to the fractional, 

 as being not only more simple, but also more definite, and therefore more easily un- 

 derstood by all. 



December 22, 1847. — J. S. Bowerbank, Esq., F.R.S., President, in the chair. 



The minutes of the preceding meeting were read and confirmed. 



George A. K. Howman, Esq., was balloted for, and duly elected a member of the 

 Society. 



The list of gentlemen proposed as the officers and council for the year ensuing was 

 read, and ordered to be suspended in the meeting-room. 



A short notice by Mr. M. S. Legg was read, being the correction of an error in the 

 description of the construction of the Nicol's prism, given by him in his paper ' On the 

 Application of Polarized Light in Microscopical Investigations,' published in the last 

 number of the Transactions of the Society. 



A paper entitled ' Observations on the Anguinaria spatulata,' by Geo. Busk, Esq., 

 was read. This paper was stated by Mr. Busk to be a continuation of his former 

 communication on the Notamia Bursaria, read at the October meeting of this Society. 

 This zoophyte — the Anguinaria spatulata or snake coralline of Ellis — is stated by Dr. 

 Johnson to be " not common," but was found by Mr. Busk in great abundance in the 

 same locality as the Notamia. It is parasitical upon Fuci, and is not unfrequently 

 associated with other polypes on the same plant. Its character, as given by Dr. John- 

 son, appears to be incorrect in several particulars, which it was partly the object of 

 this paper to point out and rectify. It consists, like all its congeners, of two distinct 

 portions, the radical part and the polype cells. Its origin or base is a more or less 

 rounded disc, of small size, probably divided into compartments, from each of which 

 arises a primary branch or tube, which is directly continued into a polype cell, but 

 without any internal communication. The polype cell is at first continued in a line 

 with the radical branch, but soon turns up at a right angle and assumes an erect po- 

 sition ; after ascending in a nearly straight line for a certain distance it curves with a 

 gentle sweep, and terminates in an expanded extremity, at the point of which — and 

 not at the side, as stated by Dr. Johnson — is the opening through which the polype 

 protrudes. The continuation of the radical portion is effected by the formation of a 

 bud at the angle where the polype cell turns up, which bud becomes a narrow tube, in 

 all respects similar to the primary one, and after running a short distance turns up in 

 a similar manner and terminates in a polype cell, and so on continuously. The radical 



