538 MR ROBERT KIDSTON ON 



the vascular system has only connection with the central of the three cicatricules of the 

 leaf-scar. 



In regard to the small scar which Stur calls the ligule-scar, and the point of attach- 

 ment of the sporangium, I do not see on what sound evidence these terms have been 

 applied to the structures indicated ; and though I am unable to explain their function, the 

 terms appear to me very misleading. 



In Lepidodendron and Lepidophloios the sporangia are borne on the bracts — not 

 attached to the stem — and there is no ligule associated with the sporangia ; hence such 

 terms as those adopted by Stur for small scars on the leaf-cushion seem to be quite 

 misplaced ; and further, they do not appear to be present on all species of Lepido- 

 dendron. 



1880. Lepidophloios, Schimper. " Zittel. Handbuch der Palaeontologie," Abth. ii. 



Palceophytologie, p. 193. 



Schimper here treats provisionally as distinct genera, Lepidophloios and Lomato- 

 phloios, and in regard to the latter, owing to the sparseness of material, does not state 

 any decided opinion as to its relationship with Lepidophloios, leaving the subject an 

 open question. 



1880. Lepidophloios, Lesquereux. Coal Flora, vol. ii. p. 418. 



Lomatophloios, Corda (ex part), is here united with Lepidophloios. The genus seems 

 to be very rare in the United States, and the specimens Lesquereux has been able to 

 examine were fragmentary and imperfect ; hence, for his knowledge of the genus, he 

 was largely dependent on the writings of others. Of the species Lesquereux described, 

 many of his specimens are very imperfect, and it is doubtful if some of them really belong 

 to this genus. 



1880. Thompson. "Notes on Ulodendron and Halonia" Trans. Edin. Geol. Soc, 



vol. iii. part iii. p. 341. 

 In his concluding remarks, he says — " That Ulodendron and Halonia were closely 

 allied Lepidodendroid plants ; that, on presumptive evidence, Professor Williamson's 

 suggestion may still be maintained, viz., that Ulodendron and the biserial 'Halonia' 

 may possibly represent portions of one and the same form ; and that, in this case, 

 the specimens denominated Halonia formed the terminal or young branches of 

 Ulodendron." 



I have merely to remark that I have never yet seen a " biserial " Halonia, nor am 

 I aware where such a specimen is described. It is true that Morris described a fossil as 

 Halonia disticha, but his fossil is in reality a specimen of Sigillaria discophora, Konig , 

 sp., and not a Halonia, as he supposed* 



* Trans. Geol. Soc. Lond., 2nd ser. vol. v. pi. xxxviii. fig. 1, 1840. 



