400 Mb. a. w. waters on the relationships 



sufficient for classification, yet it is important to see how Ear otlier characters 

 run through all or most species. 



The basal * structure of (Jupularia canariensis has a series of parallel 

 chambers (PI. 29. fig. 1) filled with a granular substance and having a 

 connection from each chamber to its neighbours through rosette-plates. 

 The lateral walls are parallel with the axis of the zoarium. These chambers 

 are partly shown by Busk in his L. canariensis, ' Crag Polj'zoa,' pi. 2. fig. 2 e, 

 and would have been called kenozocecia by the late Professor Levinsen, 

 while lleuss and others have named the chambers at the base of Batopora 

 "abortive cells/' In Cupularia the walls of these chambers, as well as those 

 of the zooccial and vibracular chambers, are lined by large square flat cells 

 with a small nucleus (PI. 29. figs. 2 & 3). These large cells seem to occur 

 generally in the Selenariadse. 



In C. Loioei, Busk, looking at decalcified and stained preparations, with 

 the opercular wall in focus, a number of small bundles of muscles are seen, 

 which pass from the frontal membrane through the large frontal calcareous 

 pores (PI. 30. fig. 1). Similar muscles occur generally in the Microporidse. 

 Looking at the same preparation from below, the zocecial chambers are seen 

 separated by a considerable free space, and to about the median line of ihe 

 zocecial chamber there is a row of singlet muscles, or sometimes a small 

 bundle, passing from the lower surface of the zocecial chamber to the lower 

 surface of the zoarium (PI. 30. figs. 2 & 3). No structure at all comparable 

 to this has been mentioned as occurring in the Bryozoa ; however, the" basal 

 calcareous wall gives an indication of their occurrence, by a groove along 

 the line of the muscles, with a pore at the end (PI. 30. fig. 4) ; and there is 

 no doubt that fossil C. umbellata, Defr., and some other species, had the same 

 muscular arrangement. Further examination of spirit specimens may reveal 

 points which could not be distinguished in the very limited material 

 available. 



Whether a new genus should be made before more material and species 

 have been examined is perhaps an open point, though it does not seem that 

 species having such different structures as C. canariensis and C. Loioei can 

 remain together. If found advisable, C. Lowei, C. umbellata, etc., might be 



* I shall throughout the paper, so far as possible, consider the colon)' as seen in the 

 position in which it first grows on its support, so that the opercular wall is the upper surface, 

 while the lower or base rests upon the support in the first stage. In doing this no opinion 

 is pronounced on the suggestion that some mature forms may live in a reversed position, and 

 for the same reason the base of the cone is alwa3's shown below, even though possibly it 

 might be more correct to reverse it in the mature forms of some species. 



t In a very good specimen the threads to the dorsal surface are fine lines, about the same 

 size as the frontal opesial muscles, but in a specimen in which some changes have taken 

 place they are largo and alternately light and dark, that is striated, which may be a 

 histological change. At each end the muscle widens out (as in PL 30. fig. 28). 



