Johnson — Is Archceopteris a Pteridosperm? 119 



Like the American and Canadian, the Russian specimens suffer from lack 

 of adequate illustration. Curiously enough, Schmalhausen states tliat when 

 better illustrations of the species of Arohseopteris already described are 

 available, and when earlier deposits come to be revealed, the spiral arrange- 

 ment, he thinks, will be found to be not confiued to A. archetypus. 

 Schmalhausen lays some stress on the greater extent of preservation of the 

 lamina, especially at the distal end, in the fertile pinnule of A. archeti/pus, 

 by contrast with all other species of Archseopteris described. To this I shall 

 return in the description of A. hibevniea. In the second species of Archse- 

 opteris — A. fissilis — the bipinnate frond in which the pinnae are distichously 

 arranged shows pinnules dichotomously divided into four or eight filiform 

 vascular processes, leaving very little undivided basal lamina. The fertile 

 pinnae show the usual arrangement of fusiform or club-shaped sporangia 

 arranged on the upper side of the filamentous pinnule. The sporangia are 

 shown, however, not arranged singly like the teeth of a comb, but two, three, 

 or more togetlier on a common stalk. Each pinnule bears eight sporangia 

 on its upper side, while the number in A. archetypus may be as high as forty. 

 Allowing for the finely-divided state of the pinnule, the venation is on the 

 same plan in A. fissilis as in A. avchety^nis and other species of Archseopteris. 

 Both A. archetypus and A. fissilis have since been recorded from EUesmere 

 Laud (78° N. Lat.) by Nathorst (19), by whom they are also fully illustrated. 



Indeed there is nothing more interesting in connection with Archaeopteris 

 than the discovery of its contemporaneity in similar estuarine deposits in 

 such different regions as Southern Ireland, Central Europe, Bear Island 

 (74° N.), EUesmere Land (78' N.), and the eastern part of North America, 

 in both Canadian and American territory. 



Heer was the first in 1870 to record its occurrence (22) in Bear Island, 

 where fragments of A. Roemeriana, Gopp. were obtained . Nathorst, however, 

 gave the most complete account of the Bear Island deposits in 1902, noting 

 A. intermexlia, Nath., A. fimbriata, Nath., and A. Boenieriana, Gopp., the last 

 two in a fertile state. All, too, are well illustrated by him, as in the case of 

 the two EUesmere Land species. 



Schmalhausen compares his A. fissilis with Sphenopteris petiolata, Gopp. 

 from the Cyperidiuete-strata near Saalfeld, now known to be Upper 

 Devonian, and contemporaneous with the South Eussiau and Kilkenny 

 deposits. The two plants, he notes, show the greatest similarity to one another, 

 and differ in detail only iu their vegetative organs. The comparison is 

 interesting, since Brougniart, writing to Griffith in 1857, refers to Unger's 

 Saalfeld discoveries (23) as likely to throw light on the Kilkenny fossils. 



Schmalhausen sees also some likeness iu A. fissilis to Sphenopteris 



