172 



and boldly arched distal cnil, Uk' free margin of which gencralh' tcrminales in 

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

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

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

 more or less deep depression of somewhat dilTeienl extent; l)nt the greater part 

 of the frontal surface of the zoo'cium is always arched. \n 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 zonecium that it is difficult to discern 

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

 tlanges and has the form of a rectangle, the two sides of which are carved in- 

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

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

 seem to reach the basal wall (fig. 2 d). Tlae 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 polypide-tube and besides, it is furn- 

 ished at each proximal corner with a prolongation fitting into the o])csiular 

 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 ocrcium into two parallel [)rocesses that grade into the 

 arched lateral i)arts of the frontal wall. Between these processes and the free 

 margin of the ooecium we find a ([uadrangular opening forming something like 

 a vestibule to the zoo-cial aperture. The oo'cia spring from the surface of a 

 similar, distal prominent [)art as is found in tlie other zooccia, but it is flatter, 

 and the two swellings, which enclose the ooecium 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 ocecia have but a rather small 

 opening. 



The avicularia, which are scattered among the zonecia 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 1 have examined a dry coloni from the Antarctic Ocean. To 



' no. |). 29, |)l. Ill, fig. 21. 



