60 Mr. H. J. Carter on the close Relationship of 



ing an irregular radiated structure, in the midst of which, 

 as well as in the intervals between them, may be seen the open- 

 ings of one, two, or three radial tubes (here 14-1800ths inch in 

 diameter), in accordance with the size of the eminence (fig. 16,6). 

 The difference in diameter or size of the eminences arises from 

 the columns, as they progress outwardly, having to supply 

 offsets or branches, here and there, to fill up the increased space 

 caused by their radiation ; while the interval between the emi- 

 nences is supplied by the surface of the last-formed lamina. 

 I regret that the illustrations are so small ; but the object has 

 been to keep them of the natm'al size as much as possible, for 

 comparison, leaving the reader to magnify them into diagrams 

 if he should feel so disposed. 



Ohs. To say that the tissue-fibre of Parkeria in its present 

 condition was identical with chitine in the living state would 

 be absurd ; but to say that calcareous fibre under this form 

 does not occur in any recent organism of this kind, and that 

 chitinous does, as in Hydractinia and especially in Chitina 

 eri'copsis, is indisputable. Again, the uninterrupted homo- 

 geneity of the tissue-fibre of Parkeria is incompatible with the 

 more or less cored tissue-fibre of sponges. Moreover, that a 

 thick laminated chitinous species of Hydractinia of consider- 

 able thickness does occur, is proved by the recent species 

 figured under the name of H. Icevisjnna in the ' Annals ' 

 iJ'C.). 



Having thus identified the tissue-fibre of Parheria^ we come 

 to its structural or architectural developments ; and here again 

 we have undoubtedly the " tubes !' foreshadowed in our descrip- 

 tion of Hydractinia^ and identified in those of the fossil species 

 (viz. H. 2)liocena)j indicative of a coenosarcal stolon-tubulation 

 united throughout the interior, and finally opening on the sur- 

 face. As to the " annulation " seen in the latter, that could 

 hardly be expected, from the irregularity of the reticulated 

 tissue-fibre ; at the same time, if every individual were exactly 

 alike, there would be no occasion for specific distinction. 



The possibility of Parkeria being a species of Foraminifera 

 rested chiefly on the presence of a " primordial chamber-cone " 

 and the tissue-fibre being arenaceous like the composition of 

 Lituola^ &c., which have both been shown to be untenable ; 

 while the absence of a primary or embryonic chamber in the 

 centre and the presence of reticulated tissue-fibre in its stead, 

 together with the neighbouring structure that I have mentioned, 

 the elaboration of the whole of the architectural structure of the 

 test out of reticulated tissue-fibre, and the presence of one or 

 more comparatively large foreign bodies in the midst of it are 

 all facts, so far as my experience extends, singly or all to- 



