203 



between the two parts of Ihe cryplocysl ot which one is ascending lowanls Ihe 

 apertnre the other descending towards the above-mentioned senii-ellii)lical bound- 

 ary ridge, the two parts forming an oljluse angle. The portion on the proximal 

 side of the opening is also somewhat thickened. The contracted, proximal part 

 of the zocrcium consists of a flexible chitinoiis mass decreasing in thickness as 

 it continues through the thick-walled calcareous bottom, distally to which the 

 narrow lumen suddenly expands into a spacious, asymmetrical cavity, furnished 

 on one side with a blind sac-like continuation directed proximally, which we 

 may term the proximal recess. All the zott'cia are on the whole very asymmetri- 

 cal, which may be seen more or less distinctly in all the different structural 

 features. Thus the basal recess and the larger of the two opesiulai are situated 

 on the same side of the zoa>cium, towards which the above-mentioned inner 

 ridge inclines and the semi-elliptical boundary ridge has also a more or less 

 distinct inclination towards that side. While this side in the axial zoa^cia is the 

 right or the left alternately, it is in all other zoa^cia the one facing the central 

 line of the colony. 



The obli(iuely ascending distal wall (figs. 3 d, 3 c), situated rather far back 

 and bent in an arch from side to side, has within its basal nuirgin a series of 

 small single-pored rosette-plates, and according as the zoa^cium is ilistally con- 

 nected with one or three others its distal end is undivided or divided into three 

 smaller pore-chambers. In an undivided pore-chamber I have found <S— 9 rosette- 

 plates. 



On the dry colonies examined I found some branches ending in one or two 

 long, narrow, somewhat bent, almost cylindrical internodes, which on the frontal 

 side a little above the proximal end had a pear-shaped hole. It seems natural 

 to suppose that all the terminal zooecia end in this way, and it is possible that 

 their function is similar to that of the cylindrical internodes in Chlidonia. 



The ocEcia are borne by separate, small branches (fig. 3 a), which may spring 

 partly from most of the axiai zooecia and partly from a smaller number of the 

 lowest zoa'cia of the second order. They are situated a little proximally to or 

 on a level with the semi-elliptical ridge half-way towards the margin of the zooc- 

 cium, and in the successive zooecia alternately on the right and the left side. In 

 each of these branches, which have an arch-like bending and stand out almost 

 vertically from the surface of the colony, we may besides the two ocrcial valves 

 also distinguish between a gonozoa'cium and a kenozoa^cium, which unites the 

 former with the zoa^cium. In the stalk-like kenozooecium (figs. 3 m, 3 n, 3 o), 

 we may distinguish between a longer and thicker, calcified, ovally club-shaped 

 central part and two shorter, cylindrical, somewhat bent terminal parts consisting 



