169 



the polypide-tube is in most zooecia formed by the basal surface of the latter; 

 but in this species it is as common to find polypide-tubes with an independent 

 basal wall. Except in S. lateralis, the cylindrical polypide-tube of which has only 

 a more or less strongly outwards bent distal margin (figs. 7 a — 7 c), the qua- 

 drangular or trapeziform frontal wall of the polypide-tube is in the other species 

 provided with more or less protruding, frontally directed marginal flanges. In 

 S. neozelanica (figs. 3a, 3d) and S. neozelanica, var. magnifica (figs. 4a, 4c) 

 these form a long and, especially in the former very narrow tube, which is closed 

 internally by the frontal wall of the polypide-tube. The bottom of this tube is 

 provided with pores which may also appear on the adjoining parts of the opes- 

 iular ingrowths. 



Siphonoporella delicatissitna Busk. 



Membranipora delicatissima Busk, Quart. Journal micr. Sci., n. ser., Vol. I, 

 1861, pag. 153, PI. XXXIV, fig. 1. 



Siphonoporella delicatissima Harmer, Quart. Journ. micr. Sci., n. ser., Vol. 43, 

 1900, pag. 231, PI. 13, figs. 42, 43. 

 (PI. VI, figs. 3 a— 3 d). 

 The zooecia narrow, rectangular or longitudinally hexagonal. With the excep- 

 tion of the arched, sometimes coarsely transversely striated gymnocyst developed 

 in the proximal part of the zocecium, which in its middle measures one-fifth at 

 most of the whole length of the zocecium, the frontal surface is otherwise mem- 

 branous. The finely granular concave cryptocyst, which joins the gymnocyst in 

 a semi-elliptical boundary line, sinks distally in the shape of a pent-roof towards 

 the basal surface, which it reaches in a continuous line formed by two une- 

 qually large curves, which meet at an acute angle (fig. 3 d). The polypide-tube 

 is situated closer to one lateral wall, while at the same time it inclines towards 

 the opposite one. It is a rather long, cylindrical tube which generally increases 

 in width distally and terminates in a somewhat expanded margin provided with 

 a number of finer and coarser teeth, of which some may be rather long and 

 pointed, sometimes branched. The surface of the polypide-tube may also be more 

 or less nodulous, and these nodules may sometimes be annularly disposed. We 

 may designate the side of the polypide-tube nearest the one lateral margin of 

 the zocecium as the inner and the other as the outer side. The freely projecting 

 part of the polypide-tube just described is continued proximally under the pent- 

 roof-shaped cryptocyst cover, and this proximal part, which is obliquely truncated 

 at the end (fig. 3 c), is clearly visible through the cryptocyst. . The boundary be- 

 tween the distally and proximally directed part of the polypide-tube is formed 



