Carboniferous Fossils from Siani. 175 



Surface of pygidium very finely granulated. Dimensions : length, 

 5 mm. ; width, 8-5 mm. 



Remarks. — Two pygidia occur on opposite sides of the same 

 piece of rock, one with the shell preserved and the other in the 

 condition of a hollow impression. These were identified by 

 Professor Hughes as Proetus. The very short pygidium and small 

 number of segments of which it is composed seem to necessitate 

 the reference of these specimens to this genus rather than to Phillipsia 

 or Griffithides, and we may compare it with the Lower Culm species, 

 Pr.oetus sp. a^ and Pr. coddonensis Woodw.^ from North Devon. 

 Pr. ])ostcarbonarius Gemmellaro,'' from the Sosio Limestone of 

 Sicily, seems also to be allied to our form. It is undoubtedly distinct 

 from the species Proetus ellipticus Mansuy,"* from the Dinantian 

 of Eastern Yunnan, which seems to be the only species of the genus 

 previously recorded from the Carboniferous of South-Eastern Asia. 

 The occurrence of this typically Devonian and Silurian genus in 

 these Siamese beds is a token of their low stratigraphical position 

 in the Carboniferous. Apart from the Devonshire species, the only 

 Carboniferous representatives on the Continent are Pr. (Dechenella) 

 angustigenatiis Leyh, and Pr. (D) hojoensis Leyh, from the 

 Posidonienschiefer of the neighbourhood of Hof.® 



PhillijJsia aff. silesiaca Scupin. (PL II, Fig. 18.) 

 One small imperfect middle shield occurs in the collection, 

 measuring between 3 and 4 mm. in length, but there is sufficient 

 preserved to decide its reference to the genus Phillijjsia, though the 

 species cannot be determined. The glabella is semi-oval, somewhat 

 elongated, widening slightly posteriorly, with nearly straight sides, 

 and it consists principally of a large somewhat swollen median lobe 

 overhanging the front end, with a pair of very short lateral, nearly 

 horizontal furrows indenting its sides and marking ofi incompletely 

 a pair of very small lateral lobes, which are bounded posteriorly by. the 

 deeper and stronger short oblique basal furrows not reaching the meso- 

 occipital furrow. The basal lobes are small, swollen, subtubercular, 

 and subtriangular, and they are widely separated from each other 

 by about three times their width. The eye-lobes are long, narrow, 

 and rounded, and are closely pressed against the sides of the 

 glabella, reaching from a point about half its length to behind the 

 basal lateral furrows. The fixed cheek behind them seems to be 

 very small, but this part is not well preserved. Several species of 

 this genus have been described from the Lower Culm near Hof ^ and 

 from the Lower Carboniferous of Silesia, and ours especially 



1 Woodwcard, Quart. Journ. Geol. Soc, vol. li, 1895, p. 648, pi. xxviii, 

 figs. 7, 7a. 



2 Woodward, Geol. Mag., Dec. IV, Vol. IX, 1902, p. 483, PI. XX, Figs. 5-11. 



3 Freeh, Leth. Geogn. I, PalcEOZ., Bd. ii, Lief, iv, 1902, p. 506, t. 596, fig. 5. 

 * Mansuy, op. cit., vol. i, fasc. ii, pt. ii, 1912, p. 85, pi. xvi, fig. 2. 



^ Leyh, Zeitschr. deut. geol. Gesell, xlix, 1897, pp. 522, 524, t. xvii, figs. 1, 2. 

 « Ibid., pp. 526-7, t. xvii, figs. 3, 4. 



