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coarsely granular contents of the radical tube have no communication 

 with the polype cell. The polype cell is at first continued in a line 

 with the radical tube from which it originates, but soon turns up at a 

 right angle and stands erect upon the object on which the Bryozoon 

 is growing. After ascending in a nearly straight line for a certain 

 distance it curves with a gentle sweep, and terminates in a slightly 

 expanded extremity, at the apex of which, and not at the side, is the 

 opening through which the polype protrudes. The continuation 

 of the radical portion of the zoophyte, or of that creeping fibre, as it 

 appears, which is adnate to the foreign base, is effected by the forma- 

 tion, at the angle where the polype cell turns up, of a bud containing 

 granular matter, which becomes a narrow tube, in all respects similar 

 to the primary radical tube, and which, like it, after running a short 

 distance, terminates in a second polype cell resembling the first, and 

 so on continuously, to an uncertain number. The growth of the polype 

 cell appears to precede in some degree that of the radical tube continu- 

 ous from it, but it is not necessary that the growth of the former should 

 be completed before the latter makes its appearance. The develop- 

 ment of these two parts seems to be carried on in the usual way; viz., 

 first, in the appearance of a rounded bud filled with granular matter, 

 which gradually increases in length, and the contents of which are 

 finally moulded or resolved into the proper contents of the cell, of 

 which the bud constitutes the origin. In some cases more than one 

 bud of a radical tube arises at the angle of the polype cell, and in 

 this way arise the apparent branches of the creeping stem. The walls 

 of the radical tubes and of the polype cells consist of a thin transparent 

 horny material, which is insoluble in weak acids, and strengthened or 

 rendered rigid, except in one part, by the deposit of calcareous matter. 

 In the radical tubes, and on the dorsal or upper surface of the di- 

 lated extremity of the polype cell (fig. 4), this earthy matter is depo- 

 sited in the form of minute angular or rounded particles, presenting 

 faint traces of a linear arrangement, but in the main body of the po- 

 lype cell, or the upright portion, the calcareous material is arranged 

 in beautifully regular rings, giving that part of the zoophyte a pecu- 

 liarly elegant appearance under the microscope. This calcareous in- 

 gredient is sufficiently abundant to render the contents of the radical 

 tubes and polype cells indistinct, and to obtain a satisfactory view of 

 these parts it is necessary to remove the earthy matter by some weak 

 acid. When this is done it will be found that the contents of the ra- 

 dical portion are, as before mentioned, coarsely granular, and the wall 

 rather thicker than those of the proper polype cell. The latter con- 



