494 H. HICES ON THE REMAINS OF PLANTS FROM THE 



felted mass ; and in the figure of the longitudinal structure of tho 

 stem, in D'Urvillea Harveyi given by Dr. Hooker (loc. cit.) an irre- 

 gular vermiform interlacing and interweaving of the cells or tubes 

 is shown, remarkably agreeing with the structure of Nematophycus. 

 It would be interesting to ascertain if the large round spore-like 

 bodies (which are here termed Pachytheca or Pachy sporangium, fig. 7) 

 are the sporangia of Nematophycus : the cells which radiate from the 

 central cavity are certainly filled with round spore-like bodies ar- 

 ranged in single file, or disposed in such a manner as to be shed from 

 the periphery or circumference of the body called Pachytheca. This 

 is manifest in the structure of one of these cut through and shown 

 under the microscope (fig. 9). The large tubes or cells, constituting the 

 stem structure, which appear here and there to contain round spore- 

 like bodies similar to these, do not really do so ; they are, I believe, ac- 

 cidentally scattered here and there, and appear to be within rather 

 than upon the tubes in the microscopic sections. 



On two of Dr. Hicks's rock specimens there are singular honey- 

 comb-celled bodies having all the appearance of being coriaceous or 

 membranous capsular bodies, or sporangia ; the outer portion was 

 definitely composed of either four- or six-sided cells. This sac-like 

 body may have played some part in the history of Nematophycus. 

 Under any circumstances they are worthy of notice, and are un- 

 doubtedly organic. 



The plant called Prototaxites by Dr. Dawson, from the Gaspe 

 beds, of Devonian age, was one of the oldest plants then known ; the 

 previously known oldest plants are mere fragments of woody matter : 

 these occur with Pachytheca in the Upper Ludlow, of the Ludlow 

 area ; and no older British rocks have, until now, yielded any. 

 Looking at the probable distribution of a marine flora the plants 

 composing which were of such magnitude and probably widely 

 spread over the Devonian sea-bed, we naturally turn to the origin or 

 source of the Gaspe Devonian species. The presence of Nema- 

 tophycus in the Denbighshire Grits is proved by these researches of 

 Dr. Hicks ; but no remains of a similar kind have been found 

 through the higher beds of the Woolhope, Wenlock, and Ludlow 

 rocks — except at the close of the Ludlow, in the Down ton shales, 

 if the seed-like bodies termed Pachy sporangium or Pachytheca are 

 to be regarded as portions of Nematophycus. If they have no relation 

 to each other, then we have to account for the wide distribution in 

 time of both — Nematophycus from the Denbighshire Grits to the 

 Devonian, and Pachytheca from the Denbighshire Grits to the Upper 

 Ludlow. We are warranted, I think, in believing that there is far 

 less chance of these being one species than modified descendants 

 from an older stock, the entire area never having been dry land at 

 one time since the deposition of the Denbighshire Grits ; I therefore 

 give this the specific name Nematophycus Hicksii. I look forward 

 to finding the remains of this group of Alga? in rocks of far higher 

 antiquity ; for it is evident that marine plants of such colossal size 

 as the Gaspe species is known to have been could not then have 



