96 Arber. — A Revision of the Seed Impressions of the 
Seeds of medium size, oval or elliptical, broadly rounded at both 
extremities, about 2*5-3 cm * l° n g> and 1 *3-1*8 cm. across, with about nine, 
rather prominent and somewhat distant, longitudinal ribs on each side, 
approximated at base and apex, (?) sometimes confluent. 
(2) Platyspermum elongatum , Kidston (PI. VI, Fig. 12). 
Type Rhabdocarpus elongatus , Kidston, ‘ Trans. Geol. Soc. Glasgow/ 
vol. viii, p. 70, PI. Ill, Fig. 6 , 188 6. Recorded from the Middle and 
Lower Coal Measures of various coalfields in the Midlands and in 
Scotland. 
Seeds small, very narrow, oblong, up to 2*3 cm. long, and 3*5-5 mm. 
wide, rounded at the apex, gradually contracted towards the base. The 
testa has four or more longitudinal ridges on each side. 
(3) Platyspermum Kidstoni , sp. nova (PI. VI, Fig. 9). 
Type Rhabdocarpus midtistriatus } Kidston, ‘Trans. Roy. Soc. Edinb./ 
vol. xxxiii, p. 404, PI. XXIII, Fig. 4, 1888. Recorded from the Upper 
Coal Measures ofRadstock. 
Seed oval, 3*5 cm. long, and 2*i cm. broad, with about eight longitu- 
dinal ridges on each side. Ridges approximated at the apex and base. 
Between the ridges numerous fine, parallel striae occur. 
(4) Platyspermum multistriatum (Presl.) non Kidston (PI. VI, Fig. to). 
Type Carpolites midtistriatus , Presl. in Sternberg, ‘ Vers. Darstell. Flora 
d. Vorwelt/ vol. ii, Heft 7, p. 208, PI. XXXIX, Figs. 1-2, 1838. From the 
Middle Coal Measures of North Staffordshire. 
Seed ovate, very broad at one end, somewhat more pointed at the 
other, 3-4 cm. long, 2*2 cm. across at its broadest part. Ribs about nine on 
each surface, not approximated at apex nor base. 
(5) Platyspermum rugosum , sp. nova (PI. VI, Fig. 13). 
Types Nos. 1655, 2337, Carbon. Plant Coll., Sedg. Mus., Camb. From 
the Upper Coal Measures of Radstock, Somerset, and the Middle Coal 
Measures of the Mattice Hill Boring, Kent, at 1,484 feet. 
Seed elongately elliptical, bluntly pointed at both ends, up to 4 cm. or 
more in length, and about 2 cm. across at broadest part. Ribs broad, 
prominent, separated by wide, shallow grooves, three to five on each side of 
seed, ribs approximated at base and apex. Testa smooth or very finely 
striated. 
Genus Cornucarpus, gen. nova. 
Seed small, not winged, triangular in shape, the apex of the triangle 
being directed downwards and ending in a short stalk, one side of the 
triangle forming the broad apex of the seed. Two well-marked horns 
project from the angles at the apex. A median ridge may occur. 
