Mr. H. J. Carter on Stromatopora clartiugtoniensis. 345 



less enveloped in the Stromatoporai, possess the tabulated 

 character, so that if Stromatopora did not do so it would be 

 an exception. Nor must it be fancied that the tabulae in 

 Stroniatopora and Millepora are totally different from what 

 occurs generally in that family of the Hydroids to which I have 

 likened the former. On the contrary they do occur, although 

 in a modified form, in the Hydractiniidai and in the annular 

 constrictions of the flexible Hydroids, as I have already 

 shown (Ann. & Mag. Nat. Hist. 1877, vol. xix. pi. viii. 

 fig. 4, <j (j, and figs. 9 and 12). 



Having thus described the tabulation in Stromatopora, let 

 us now direct our attention to that species in which it first 

 presented itself to my notice, since the astrorhiza here, in 

 some instances, far exceeds in size the largest given by Baron 

 Rosen, viz. that in Stromatopora astroites ('Naturder Stroma- 

 toporen,' Taf. ii. fig. 6; and ' Annals,' 1879, vol. iv. pi. xv. 

 fig. 1) ; so it is just possible that the Dartington species may 

 not have been publicly noticed, and hence it is desirable to 

 give its principal features, so far as they are at our command ; 

 but before doing so it will be as well to recall to mind what 

 I stated and illustrated respecting the division of the ccenen- 

 chymal structure of the Stromatoporce into " rectilinear and 

 curvilinear," viz. that of course this was " subject to modifi- 

 cations which more particularly belong to the description of 

 the species respectively" ('Annals,' 1879, vol. iv. p. 254). 

 These " modifications " consist of the passage of one kind of 

 structure into the other, so that the species in this respect may 

 be more allied to the former than to the latter, and vice versa. 

 There is also a difficulty in getting the real or original surface 

 of the species, chiefly on account of weathering and decomposi- 

 tion, whereby a most important distinction may be lost; while 

 the general form may be influenced by that of the organism over 

 which the Stromatopora may have grown [ex. gr. a branched 

 coral) — just as at the present clay a number of specimens of 

 calcareous Polyzoa dredged in Bass's Strait for the Liverpool 

 Free Museum, by Capt. Cawne Warren, have been found to 

 derive their varied form from that of different kinds of sponges 

 which they have overgrown. Hence it again becomes diffi- 

 cult to determine what the original form of a Stromatopora 

 was, further than that, when not influenced in the way men- 

 tioned, it assumes a massive state of concentric lamination like 

 that of any other coral of a like growth, exceeding sometimes 

 two or three feet in diameter. Following is a description of 

 what we know of the Dartington species : — 



Ann. & Mag. N. Hist. Ser. 5. Vol. vi. 25 



