4 THE VOYAGE OF H.M.S. CHALLENGER. 



Such was the general state of knowledge, or rather of ignorance, in regard to the 

 zoological characters of Orhitolltcs and Mar(jino])ora, at the date (1848) when I under- 

 took a careful microscopic examination of Mr. Jukes's specimens of the latter, the results 

 of which led me to compare their structure with that of the fossil Orlntolites complanatus. 

 These results I communicated to the Geological Society in May 1849, and they were 

 published in its Quarterly Journal for Feb. 1850. The place universally assigned to these 

 genera by zoologists and palteontologists being in immediate proximity to Lunulites 

 (whose Bryozoic nature could not be reasonably doubted), — and the living Soritidce of 

 Prof. Ehrenberg having been described and figured as Bryozoic, on the basis of personal 

 observation, by the microscopic autocrat of the time, whose dicta it was heresy to ques- 

 tion, — I entered upon the investigation without the least suspicion that this organism was 

 to be regarded in any other light ; and that I was not at once undeceived, was mainly due to 

 the fact that among the small number of specimens first placed in my hands l)y Prof. E. 

 Forbes, there was not one by any means perfect, — all being more or less abraded, and 

 not one possessing that central " nucleus " which is the portion most indicative of their 

 Foraminiferal afiinities. Nevertheless, the marked dissimilarity in structure which 1 

 found to exist between the calcareous disk of Orhitolites, and the skeleton of Lunulites or 

 any other undoubted Bryozoa, made me even then express myself doubtfully as to its 

 title to be closely associated with them. I found that between the recent Marginoioora 

 ro'tehralis of Quoy and Gaimard, and the fossil Orhitolites coniplanata of Lamarck, the 

 dift'erences are so trivial as to amount at most to a specific distinction ; so that the later 

 genus must be abolished, and the Australian disk be ranked as the recent type of the fossil 

 so abundant in the Calcaire Grossier. And I showed that, in the one as in the other, the 

 " cells " (which I now designate as " chamberlets ") are normally closed-in over the whole 

 surface ; that the two surfaces are separated from each other by an intervening stratum, 

 traversed by a set of round columnar cavities of its own, with inter-communicating 

 passages ; that each superficial cell communicates with this intermediate cavitary system 

 by two small apertures ; and that the only real external orifices are the minute pores at 

 the margin of the disk, which do not communicate directly with the cells of the 

 superficial layers, Init are the openings of passages leading to the outermost series of 

 columnar cavities in the intermediate stratum. To this complicated arrangement I could 

 find no parallel in the Class Bryozoa, but I was equally unaljle to indicate any jiarallel 

 to it elsewhere. 



At what date the Foraminiferal nature of Orhitolites first came to be suspected by 

 M. d'Orbigny there is no means of knowing ; but in the year 1852 (Cours Elementaii'e de 

 Paleontologie) he assigned it a place in that group ; creating for it, and for some other 

 genera having a like discoidal form, the Order Cyclostegues, which he defined as 

 follows : — " Animal compose de segments nombreux, places en lignes circulaires. CoquUle 

 discoidale, composee de loges concentriques, simple ou multiples ; point de spirale." 



