70 Mr. H. J- Carter on the close Relationship of 



gential sections must appear throughout the fossil), as well as 

 between the stellates ; while the lateral section of the tubes 

 showed that thej were continuous through several laminge, 

 and possessed of the diaphragms (fig. 21, a) seen in H. plio- 

 cena (fig. 10, a), and identified herewith the annulation of the 

 coenosarcal stolon-tubulation of Hydractinia ecfiinata (fig. 3) . 

 Although, however, the tubes themselves appear continuous, 

 their interior may be, and evidently is, divided hy diaphragms 

 of some kind, as before noticed in comparing the radial tubes 

 of Farheria with those of Tubipora musica. The " intertu- 

 bular communication " is a feature of Syringopora. 



Here it should be remembered that there is a marked differ- 

 ence presented by the structure of Stromatopora in the vertical 

 and horizontal sections ; that is, while the former represents a 

 series of vertical lines cut at right angles by horizontal ones, the 

 latter represents nothing of the kind, but a mass of minutely 

 reticulated tissue instead, sprinkled over with the truncated 

 ends of the radiating tubes and more or less fragmentary 

 remains of the stellates. It would therefore be impossible to 

 learn the vertical structure from the horizontal one, and vice 

 versa, here, any more than in Parheria and Lqfiusia. 



In the section of another specimen (fig. 22), called by Mr. 

 SoUas Syringopora, the apertures of the truncated radiating 

 tubes, now filled with calcspar (fig. 22, h), are larger and con- 

 fined to the area between the stellates (fig. 22, a) ; while the 

 latter, structurally, are often closed in the centre, indicative of 

 their central tubulation not having been continued throughout, 

 as we have seen in the larger species of Hydractinia echinata^ 

 &c., together with those oi H. jpliocena and H. Vicaryi. Again, 

 on account of this section having been made a little obliquely 

 to the horizontal plane, the lines of the " annulation " have 

 been brought into view most convincingly, so much so that, 

 from the large size of the tubes, they present the spiral appear- 

 ance of annulated gonothecEe in the Hydrozoa cut slantingly 

 (fig. 23). Why the parietes of the tube do not show a corre- 

 sponding annulation I cannot explain ; but in H. Vicaryi this 

 is also the case, although the casts of these tubes within them 

 are distinctly constricted (fig. VI, V). In H.pliocena, however, 

 where there is no cast and nothing but a hollow cylinder, the 

 constrictions are equally evident (fig. 10). 



The largest specimen of Stromatopora seen by Mr. Vicary 

 in the quarries of the Devonian Limestone in Devonshire, he 

 thinks must have had a hemispherical radius of 2 feet, 



Stromatopora striatella (figs. 24 & 25). 

 Subsequently Mr. Sollas brought me a specimen of Stroma- 



