B. M. S. Watson — Reptilian Femur from Scotland. 347 



the aperture divided by the crossbar into distinctly unequal 

 compartments, but not definitely mandibular. (2) Vicarious, occurring 

 chiefly at the beginning of a new row of zocecia, but sometimes also 

 in an already established row ; they are of the hourglass type with 

 the expanded upper part of the area almost circulai", but the lower 

 part narrow and with nearly upright side walls, giving a general 

 outline resembling that of a puff-ball ; the transverse bar (which was 

 probably always present in the hourglass type) is placed close to the 

 lower end of the area. 



This species occurs in, and seems to monopolize as far as its group 

 is concerned, the zones of 0. pilula and A. qtcadratiis in Hants and 

 Sussex. It is clearly ancestral to M. Griffithi. 



Membranipok.i GRIFFITHI, mihi.^ (PI. XXVI, Figs. 7, 8.) 



I take the opportunity of giving photographic figures of this 

 species to assist comparison and correct in small details the original 

 figure. The side walls show a marked tendency to thin away at the 

 upper end, and just about at the point wliere this thinning begins 

 traces of a pair of pores can be detected. The zocEcia were wrongly 

 stated to have a common external front wall ; they are subpyriform 

 with unusually prominent areal margins. The ooecia are strongly 

 bottle-necked, and appear to be not only cut away round the 

 avicularia but also somewhat cut down to them. I am able to figure 

 what is probably a perfect vicarious avicularium with the transverse 

 bar preserved. The species occurs also in the Weybourue Chalk. 



EXPLANATION OF PLATE XXVI. 

 (All figures x 12 diams.) 

 Fig. 1. Memhranipora simulacrum. Zone oi M.cor-anguinum. Gravesend. 

 ,, 2. 

 ,, 3. M. suffragista. ,, ,, ,, 



4. 



ill. boletiformis. ,, A. quadratus (restricted), 



Shawford, Hants 



6. ,, ,, A. quadratus (restricted), 



Seaford, Sussex. A thick- 



7. ill. Griffithi. Trimingbam. 



walled variety. 



III. — Oif A Femur of Keptilian Type from the Lower 

 Carboniferous of Scotlaxd. 



By D. M. S. Watson, M.Sc, Lecturer in Vertebrate Palseontology in University 



College, London. 



(PLATE XXVII.) 



WHILST looking over the private collection of fossil fishes made 

 by the late Ur. R. H. Traquair, I found a small tetrapod femur. 

 This bore no label of any kind, but was included in a series of remains 

 of Dipnoi from the Lower Carboniferous of Scotland. The texture 



' Geol. Mag., 1906, pp. 2S9-300, Fig. 1. 



