APPENDIX. 137 



rhomboidal areas, natural size, from about the middle of the same 

 specimen, and d gives a single cushion, enlarged. The scar left 

 by the shed organ is seen at c, where it is more clearly denned 

 than at c, fig. b. Figs, a and b are from a portion of the speci- 

 men showing the outer surface of the fossil; c, d, and e are 

 taken from the impression of portion of the same specimen left 

 in the matrix from which the stem has fallen out. The rhom- 

 boidal area e is from the basal end of the specimen, and here 

 the scar c is becoming effaced, though the vascular cicatrice is 

 clearly seen. On d and e the small cicatricule or pit, shown at 

 d on b, is not visible, probably through imperfect preservation. 



Fig. 26, f, shows a portion of another and older specimen, 

 drawn natural size, and g gives one of the rhomboidal areas en- 

 larged. A great difference is seen in the form of the central 

 cushion b. Here the elevation of the cushion, so prominent in 

 a and c, has entirely disappeared, and with it all trace of the 

 scar c and its vascular cicatrice, and the space is now occupied 

 by a hollow, surrounded by a raised ring bearing on its outer and 

 lower face the little cicatricule d. 



Mr. White suggests that perhaps his fig. 1, PI. XXII., represents 

 a dichotomy of the fossil. This is most probable, as Mr. George 

 West, Camerton, showed me an example which divided into two 

 equal forks. 



Awaiting the discovery of better preserved specimens which 

 would show clearly the various parts of the scar, Mr. White 

 deferred giving a definite diagnosis of his genus Omphalophloios, 

 but believing that the Somerset examples afford all the necessary 

 characters, I venture to give the following generic description : — 



Omphalophloios, White. 1898. 

 1898. Omphalophloios, White, Bull. Geol. Soc. Amer., Vol. IX., 

 p. 340. 



Cortex divided into clearly defined rhomboidal areas, within 

 which, and a short distance above its centre, is an elevated sub- 

 cordate or oval cushion with a slightly raised ring-like margin, 

 containing, a little above its centre, an oval scar with a single 

 vascular cicatrice. 



Remarks. — The genus Omphalophloios differs from Stigmaria 

 in the cortex exhibiting clearly defined and slightly raised rhom- 



