54 VAN HEURCKIELLA. 



Genera dubia v. Incertae sedis. 



VAN HEURCKIELLA PANT., 1892, 



Frustule with girdle face 

 panduriform or subcircular, 

 furnished with a large 

 marginal ocellus and with a 

 plumose flamiform structure. 



This genus was created for 

 the very curious form, repre- 

 sented in the text, which Dr. 

 Pantocsek named Van Hcurckiella 

 admirabilis. It has been found 

 in Jackson's Paddock, Oamaru. 

 Fig. 218 is an exact reproduction 



Fig. 288. Van Heurckiella admirabiVs. 



of my photograph made from the original specimen belonging to the author. 

 Dr. Pantocsek in a letter dated 26th February, 1893, writes : " Observ. Hie 

 pertinet Amphiprora cornuta, H. Chase. Grunow earn in Bot. Centr., 1877, 

 No.' 43, p. 97, pro spongiolithum libet, sed hoc incorrectum nam habitus et 

 prsesertim structura qua illius Aulisco Hardmanniano similis semper nos 

 dicat ut forma cita ad Bacillarias numeranda." The question is very difficult 

 to settle. 



On an examination of only Dr. Pantocsek's specimen I am quite disposed 

 to agree with him entirely, but since then I have discovered in Weissflog's 

 collection a diatom found by that equally learned and modest diatomist, in 

 the Oamaru deposit. This latter form only differs from that of Dr. Pantocsek 

 by the absence of granular strias. The preparation includes a demi (so called) 

 frustule similar to that represented in the text, one (frustule) arranged on its 

 face, and another arranged on its side. The latter shows at once that it is not 

 a true diatom, and that Grunow's opinion is well founded. In the work of 

 Prof. Johnson Sollas on sponges, inserted at page 39 of "Zoological Articles," 

 by Ray Lankaster, London, 1891, there will be found a long paragraph on 

 sponge spicules and numerous outlined figures representing various forms. 

 One of these (Microselerae, fig. 17 K) has a very great analogy to Van 

 Heurckiella, and I think that it really represents the Oamaru form drawn from 

 an approximate focus. 



