22 W. G. KIDEWOOD. 



except one admits that tlie polypides are capable of leaving their tubes and 

 wandering over the surface. 



The apex of each branch of the colony is bluntly pointed, and the terminal 

 eight or ten tubes have transversely terminated ends without unilateral lips, 

 slightly projecting above the general surface (fig. 10). These tubes have a length 

 of not more than 4 or 5 mm., but their width is the same as that of the longer 

 tubes situated lower down. They are curved or bent, sometimes bent as much as 

 a right-angle, and they are closely crowded. Judging from the appearance of 

 the more basal parts of the branch, it would seem that the bent portions of the 

 tubes are subsequeiitly straightened out, and that the tubes themselves become 

 more widely separated from one another, either by deposition of new intervening 

 common test, or by expansion of that already existing, though how this can be 

 effected it is difficult to conceive. The short bent tubes of the apex of the branch 

 have a bulbous swelling, not smaller than those of the longer tubes, but they differ 

 from the latter in having no hemispherical septa within them. 



In exceptionally thick pieces of the colony, e.g. a piece of 30 mm. diameter, the 

 tubes are very much longer than usual, and may attain a total length of 20 to 26 mm. 

 These very long tubes are mostly empty tubes, and the septa are much more 

 numerous than usual, and extend over 9 to 12 mm. of the tube. The part of the 

 tube occupied by the polypide up to the time of its vacating the tube is thus 

 11 to 14 mm. in length. Some of the long, uninhabited tubes have the apertures 

 closed, and a longitudinal section of the tube shows that the closing has been effected 

 by the deposition, first of some five or six thin sheets, irregular and widely separated, 

 in the mouth of the tube itself, and then several thin layers of test over the opening, 

 the stratification of these layers bearing no relation to that of the layers of which 

 the tube is constructed (see fig. 13). The "burying layers" are not continued over 

 the lip of the tube. 



In what one may conclude to be the upright branches of the colony the tubes 

 are set at the same angle to the axis on all sides, and the lips are all beneath the 

 apertures of the tubes ; in the horizontal and oblique branches, however, it is only 

 on the lower surface that the lips are strictly towards those edges of the apertures 

 which are nearest the base of the branch. The openings are few on this 

 surface, most of the tuljes having curved round so as to open at the sides of 

 the branch. 



At the sides of such a branch the lips are so situated as to be vertically below 

 the apertures of the tubes, and they are thus lateral as regards the tubes themselves 

 in their relation to the whole branch. The apertures on the upper surface of the 

 horizontal branch are arranged irregularly, and the terminal portion of each tube is 

 set nearly at right angles to the surface of the branch. The lips of the tubes are 

 mainly towards the edges which are nearest the base of the branch, but the relation 

 is not constant. Further complication is introduced by the presence of the secondary 



