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description refers, but they are found in some colonies of the variety setigera 

 originating from the samei place, which among other things differ from the main 

 form in having the lateral chambers extended over more than two-thirds of the 

 basal side of the zooeciura and their membranous walls ending in a number of 

 scattered chitinous denticles. 



A gonozooecium with its covering kenozocecium bears a certain resemblance 

 to a helmeted head and springs from a single zooecium, which again springs 

 from the mother-zooecium of a bizooecial segment. The gonozooecium and the 

 covering kenozocecium are of about the same size, and a transverse section 

 through the centre of the entii-e complex has the form of a rounded trapezium 

 with a larger frontal and a smaller basal side and with two sides converging 

 basally. The wide aperture, the operculum of which has a more strongly chitin- 

 ized marginal portion, is shared in common by the gonozooecium and the keno- 

 zocecium. It is bounded by a more strongly arched distal and a less strongly 

 arched proximal margin, in the centre of which there is a short sutural line 

 passing on to a small, transversely oval pore. The sternal area has 6 — 7 pear- 

 shaped fenestras disposed in an angle, of \yhich the two distal are situated on a 

 level with the median pore. The first pair of ribs, which limit the aperture 

 proximally, pass without any distinct boundary into the broadly rounded inner 

 cryptocyst lamina, while the second pair of ribs, which are provided with an 

 acutelj' projecting terminal part, meet in the above-mentioned suture on the 

 proximal side of the aperture. Finally, the gonozooecium is on each side provided 

 with two large, flat, generally trapeziform lateral chambers (fig. 1 1), of which 

 the distal, which has 10 — 15 rosette-plates, corresponds to the three distal lateral 

 chambers and the proximal, with about 10 rosette-plates, to the pedal chamber. 

 The real ooecium is the helmet-shaped, aiiched distal wall of the gonozooecium, 

 the proximal, obliquely ascending part of which is provided with a very large 

 number of uniporous rosette-plates. This ooecium is again covered by a keno- 

 zocecium, in which we may distinguish between a large, uncalcified, saddle-shaped 

 or horse-shoe-shaped central portion and two proximally continuous, but distally 

 widely separated, calcified portions, a frontal and a basal one. The frontal sur- 

 rounds the aperture distally and is composed of two strongly arched lateral halves, 

 which from their proximal part, situated distally to the two lateral chambers, 

 decrease in breadth towards the frontal end and are connected only by a very 

 low portion on the distal side of the aperture. The basal part, which is bent 

 towards the frontal side and which seen from the side is like the crest of a 

 helmet, is rather narrow, frontally pointed and bounded by two curved, lateral 

 margins (fig. 1 m). On either side between the two calcified portions the ooecium 



