172 



and boldly arched distal end, the free margin of which generally terminates in 

 two broad processes separated by a narrow incision and forming with eaeh other 

 an angle of 90" (figs. 2 a, 2 c). On the proximal side of the aperture and of the 

 polypide-tube we find the central portion of the frontal surface provided with a 

 more or less deep depression of somewhat different extent; but the greater part 

 of the frontal surface of the zocecium is always arched. In the middle of the 

 depression there is generally an oblong thickening which reaches the polypide- 

 tube with its distal end. The polypide-tube may sometimes be So completely 

 covered by the arched distal end of the zocecium that it is difficult to discern 

 its frontal part, which is surrounded by strongly projecting, frontally directed 

 flanges and has the form of a rectangle, the two sides of which are curved in- 

 wards a little. It is separated on either side by a long, oval incision — the two 

 opesiulse — from the lateral margins of the zooecial aperture, and its lateral walls 

 seem to reach the basal wall (fig. 2 d). The well chitinized and very low oper- 

 culum *) has a somewhat convex proximal margin corresponding (as in the genus 

 Steganoporella) to the distal margin of the poWpide-tube and besides, it is furn- 

 ished at each proximal corner with a prolongation fitting into the opesiular 

 sinus. The distal wall as well as the lateral walls are provided with a row of 

 6 — 8 small, uncalcified, most probably uniporous rosette-plates. 



The ooecia (fig. 2 a), of which a few specimens were found on the examined 

 fragment, are strongly arched, longer than broad, and they have a honeycombed 

 surface. They are enclosed between two long vertical swellings, which are con- 

 tinued proximally to the ocecium into two parallel processes that grade into the 

 arched lateral parts of the frontal wall. Between these processes and the free 

 margin of the ocecium we find a quadrangular opening forming something like 

 a vestibule to the zooecial aperture. Tha ooecia spring from the surface of a 

 similar, distal prominent part as is found in the other zocecia, but it is flatter, 

 and the two swellings, which enclose the ocecium between them, might corre- 

 spond with the two processes from the free margin of the distal end, occurring 

 in the greater part of the other zooecia. The ooecia have but a rather small 

 opening. 



The avicularia, which are scatteied among the zocecia but in much smaller 

 numbers than the latter, are small, of a triangular outline and provided with an 

 opening, which has almost the form of the figure eight. 



The colonies form free, two-layered expansions. 



Of this species I have examined a dry coloni from the Antarctic Ocean. Tq 



' 110, p. 29, pi. Ill, fig. 21. 



