344 



SCIENCE. 



[N. S. Vol. I. No. 13. 



The forms described by Nathorst in 

 1878,* though much sraaller are otherwise 

 similar to P. Buchii, and Nathorst at first 

 proposed to refer one of them to that spe- 

 cies, but later concluded that it was dis- 

 tinct and made two species, P. integrifolia 

 and P. crenata. 



In 1880 Heer described another small 

 cordate form from the Oolite of Siberia. It 

 is similar to Zigno's species and was named 

 P. reniformis.f Two years later, however, 

 he found another similar form in the Kome 

 beds, Urgonian, which is rather cordate 

 than reniform and which he called P. eor- 

 data.X Both these forms have the margin 

 entire. 



Saporta in this work has revised all these 

 forms and comes to the conclusion that 

 they cannot be ferns, and although the 

 original P. Buchii and both of Nathorst's 

 species so closely resemble dicotyledonous 

 leaves and are somewhat comparable in 

 nervation to Credneria and some fossil Vi- 

 burnums, as well as to such living genera as 

 Glechoma and Chrysosplenium, still he hes- 

 itates to class them in that group. He has 

 carefully refigured both of ISTathorst's speci- 

 mens, and also one that Nathorst figured 

 without naming but regarded as probably 

 a monocotyledon, but which Saporata con- 

 siders to belong to the same type and calls 

 P. Nathorstii. And these he carefully com- 

 pares with the Portuguese form which he 

 names P. Choffati, and classes the whole in 

 special group which he long ago created and 

 denominated the Proangiospei-ms, as repre- 

 senting the forerunners of both the mono- 

 cotyledons and dicotyledons. The Portu- 

 guese species comes from Cereal, which 

 Choffat places in the Aptian; it is therefore 

 probably somewhat higher than the Kome 



*F1. Bjuf. Heft 1, p. 42 ; Heft 3, p. 57, pi. ix., 

 figs. 2, 4. 



fFl. Foss. Arot., Vol. VI., Abtli. 1, Pt. 1, p. 8, 

 pi. 1, fig. 4a. 



Jlbid., Abth. 2, p. 11, pi. iii, fig. 11. 



beds of Greenland from which Heer de- 

 rives one of his species ; all the others, of 

 course, are of far more ancient origin, viz., 

 Jurassic, and it is not to be wondered at 

 that no one should have ventured to refer 

 them to any modern type. 



Of the other four genera refen-ed to this 

 group, viz., Changarniera, Yuccites, Delga- 

 dopsis and Eolirion, the first two come 

 fi'om the Valanginian (Neocomian) of S. 

 Sebatiao, the third fi-om the Aptian of Cer- 

 eal, and the last from the Albian of Buar- 

 cos. They all seem to be ancestral mono- 

 cotyledons. Delgadopsis occurs in two 

 forms: first, as a sort of culm or broad stri- 

 ate stem; and secondly, in the form of a 

 jointed rhizome, the swollen joints emitting 

 innumerable rootlets, which, when absent, 

 leave peculiar scars. 



Choffatia Fmneheti, regarded by the author 

 as a dicotyledon, is also a very remarkable 

 plant, and has been aptly compared by him 

 to certain euphorbiaceous forms, such as 

 Phyllanthus. It also resembles some 

 species of Euphorbia. It seems to be a 

 floating aquatic, and specimens with the 

 fibrous roots occur in the collection. In 

 some of these descending fibers occupj' one 

 side of the stem or rachis, while the floating 

 or aerial leaves occupy the other. 



Upon the whole, it cannot be said that any 

 of these higher tj^pes, found below the 

 Albian, and corresponding in age to our mid- 

 dle and older Potomac, very closely resemble 

 the plants of the same general class fi-om 

 the American beds of that age, and j^et there 

 are certain Potomac forms referred bj' Pro- 

 fessor Fontaine to Menispermites, Hederje- 

 phyllum, Protesephjdlum and Populophyl- 

 lum, whose areolate nervation somewhat re- 

 sembles that of Protorhipis Choffati. The 

 new genus Dicotylophyllum, of which he 

 finds four species in the Aptian of Cereal, 

 and which he very properly regards as a 

 true dicotyledon, somewhat resembles the 

 Protorhipis, but lacks the peculiar areolate 



