CTENIS. 233 



years by Ilaciborski and Staub. The former author, in his Fossil 

 Flora of tlie Cracow District, describes several species of Ctenis, L 

 of which exhibit circular projections on the surface of the 

 similar to those noticed by Schenk. The epidermal cells 

 of the segments bear several circular projections which Ilaciborski 

 regards as son or sporangia, and accepts as evidence of a Filicinean 

 affinity ; he was, however, unable to recognize any actual sporaugial 

 structure. In a recent paper by Staub 2 on species of Ctenis, an 

 unusually large frond of Liassic age, reaching a length of 2 metres, 

 is described under the name Ctenis liungarica ; on the segments 

 of this frond were found small depressions which the author of the 

 species speaks of as sori. We see, then, that the inclusion of 

 Ctenis among the ferns rests on inconclusive evidence, and no proof 

 has been adduced that the circular elevations or depressions on 

 the epidermal cells are of the nature of sori or sporangia. 



In his Floran vid Bjuf Nathorst 3 described some long and broad 

 leaves with reticulate venation, which he referred to a new genus, 

 Atithrophyopsis, on account of their resemblance to the simple 

 fronds of the polypodiaccous tern AntJir]>li mini. In 1879 Natlmr-t 

 transferred these Ilhactic specimens to the genus Ctenis, the supposed 

 leaves being recognized as detached and fragmentary segments of 

 a pinnate frond. Some of the figures of the Scanian fossils show 

 circular elevations on the epidermis like those already referred to. 

 -My own observations lead me to regard the evidence hitherto relied 

 on in favour of placing Ctenis among the ferns as insufficient, and 

 I believe the general habit of the leaves is a strong argument 

 for including the species of this genus among the Cycadales. 

 A specimen in the Manchester Museum from the Yorkshire coast 

 rocks was described by Nathorst 4 in 1880 as probably a new species 

 of Antlirophyopsis ; a recent examination of this specimen has 

 .afforded important information as to the nature of the supposed 

 sori described by Ilaciborski, Schenk, Kathorst, and Staub. The 

 specimen (Text-fig. 42) consists of a portion of a pinna 9 cm. in 

 length and 2'6 cm. broad, traversed by short parallel veins which are 

 connected here and there by oblique transverse veins ; the epidermal 



1 Raciborski (94), p. .">!, pis. xvi.-xviii. 



Staub (96). 



3 Nathorst (78 1 ). 



4 Nathorst (80 1 ), p. 83. 



