174 Mr. H. J. Carter on the Form and Structure 



labour, difficulty and doubt, to see, how satisfactory the exami- 

 nation of a recent foraminiferous shell, so nearly allied to Num- 

 mulites as that of OpercuUna, confirms and elucidates their ob- 

 servations. The vertical tubes passing from the surface of the 

 shell to the interior of the chambers (see Dr. Carpenter^s illus- 

 trations, fig. ] 5, loc. cit.) ; the intercameral communication {id. 

 fig. 7 b) ; the linear markings or grooves immediately under 

 the latter {id. fig. 7 c), which appear to have been produced by 

 the previous existence of a spicular cord in this position ; and the 

 radiating lines {id. fig. 15 b,b), caused by the arrangement of the 

 spicula in horizontal layers inclined towards the apex of the cord, 

 with the sloping papillary tubes on each side of it. — The " mi- 

 nute apertures " {id. fig. 7 a), which only penetrate one layer of 

 the septum, and others which open on the internal surface of the 

 walls, are probably the orifices of the ramusculi of the interseptal 

 vessels which go in this direction. — And the "perforations of 

 considerable size, which pass directly downwards from the exte- 

 rior through the superposed investing layers of the successive 

 whorls " " until they reach the floor of the chambers of the cen- 

 tral plane which they do not penetrate " {id. fig. 8 a) ; — the ver- 

 tical interseptal vessels, or an enlargement and union into one 

 tube of the ramusculi, which pass upwards and downwards from 

 the horizontal interseptal vessels as seen in OpercuUna. 



The latter, that is, the union of the vertical with the horizontal 

 interseptal vessels, I have been able to make out in some speci- 

 mens of Nummulites acuta, Sow. (Geol. Trans. 2nd Ser. vol. v. 

 pi. 24. fig. 15), which have had their cavities thoroughly infil- 

 trated with ochraceous oxide of iron ; as well as evei-ything else 

 mentioned by Dr. Carpenter ; and with the exception of the spi- 

 cula themselves, everything that I have seen in OpercuUna. 

 MM. Joly and Leymerie seem to me to have described one 

 thing and to have figured another. They describe the papillary 

 tubes, and seem, from the distance between them, to figure the 

 orifices of the vertical interseptal vessels (pi. 11. op. cit.), which 

 Dr. Carpenter has particularly described. 



The columns represented by Sowerby in Lycophrys ephippium 

 (Geol. Trans, loc. cit. fig. 15), and to which Dr. Carpenter has 

 alluded {loc. cit. p. 26), appear, to me, to be made up of the pa- 

 pillary tubes which descend from chamber to chamber (fig. %g,g), 

 and which in purely calcareous fossils are filled with a white 

 opake matter, but in those infiltrated with oxide of iron, with 

 ochraceous matter; while the intervening parts are composed of 

 the septal substance, through which the interseptal vessels pass 

 to the surface and margin in Orbitoides as well as in Num- 

 mulites. 



The same system of circulation would also appear to be car- 



