260 



2) The zooeciuni not consisting of tlirce different segments: 



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

 rib-like^processes Onchopora Busk. 



3) A compound operculum; the ocrcia without free, rib-like pro- 

 cesses Onchoporellu Busk. 



(Ichthyaria?) 



1) The compensation-sac does not o\)en outwards through a pore, 

 hut immediately on the proximal side of the operculum . Onclioporoides 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, pari I, pag. 103, 



PI. X, fig. 4. 

 Calwellia Sinclairi Harmer, Quart. Journ. Micr. Sci., n. s. Vol. 4(5, pag. 312, 



PI. 18, fig. 60. 

 (PI. XIII, figs. 7 a-7 h). 

 The zocecia, which only slightly increa.se in lireadth 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 sulural line connects this ascopore with the aperture, 

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

 aperture is surrounded by 6 ro.sette-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, ot which three are situated among tJie four elongated rosette- 

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

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

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



The ooecia are large, strongly arched and in part strongly luberculated. 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 Ihickenings, which spring from Ihe frontal wall of the just 

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



' 87, p. V>. 



