260 



2) The zooecium not consisting of three different segments : 



3) A simple operculum; the ooecia with a couple of proximal, free, 



rib-like processes Onchopora Busk. 



3) A compound operculum; the ocecia without free, rib-iike pro- 

 cesses Onchoporella Busk. 



(Ichthyaria?) 



1) The compensation-sac does not open outwards through a pore, 

 but immediately on the proximal side of the operculum . . . Onchoporoides Ortmann '. 



Onchopora Sinclairi Busk. 

 Onchopora Sinclairi Busk, Quart. Journ. Micr. Sci., Vol. 5, 1857, pag. 192, 



PI. XV, figs. 1—3. 

 — — Busk, Challenger, Zoology, Vol. X, part I, pag. 103, 



PI. X, fig. 4. 

 Calwellia Sinclairi Harmer, Quart. Journ. Micr. Sci., n. s. Vol. 46, pag. 312, 



PI. 18, fig. 60, 

 (PI. Xllli figs. 7 a-7 li). 

 The zooecia, which only slightly increase in breadth from their proximal, 

 somewhat narrowed end towards the aperture, have a little proximally to the 

 latter a linearly crescentic ascopore with frontally directed concavity and a crenu- 

 lated proximal margin. A sutural line connects this ascopore with the aperture, 

 the two curved lateral margins of which converge a little proximally. The 

 aperture is surrounded by 6 rosette-plates. Of these the two smallest have 1 — 2 

 pores each and are situated between the aperture and the crescentic ascopore. 

 The other four, which are very elongated and each provided with 3, more seldom 

 with 2 — 4 pores, surround the remaining part of the aperture. There are more- 

 over 5 round pores, of which three are situated among the four elongated rosette- 

 plates and each of the other two between an oblong and a round rosette-plate. 

 The distal wall is provided with numerous uniporous rosette-plates, and the dis- 

 tal half of each lateral wall with one extremely oblong multiporous plate. 



The ooecia are large, strongly arched and in part strongly tuberculated. They 

 are provided with rounded ridges, arranged in the shape of a fan and separated 

 by impressed lines. On the basal surface a more thickened, triangularly oval por- 

 tion is seen (fig. 7 f), on either side of which we find a few larger hollows 

 separated by rib-like thickenings, which spring from the frontal wall of the just 

 mentioned more thickened portion. From the proximal part of the latter a free, 



' 87, p. 12. 



