870 



SCIENCE. 



[N. S. Vol. III. No. 76. 



ium, Cladophlebis, Weichselia and Ruffordia. 

 Anyone who has had to deal with these old 

 names can realize the importance of Mr. 

 Seward's work. 



In Part II., so recently published and to 

 which it is proposed chiefly to draw attention, 

 Mr. Seward has taken up the Gymnosperms, 

 which, as already remarked, are the only Sper- 

 maphytic or Phanerogamic plants which have, 

 as yet, been found in the Wealden. These all 

 belong to the two orders Cycadacese and Coni- 

 ferre, unless we suppose, as Mr. Seward seems 

 to do, in common with most other authors who 

 have studied that group, that the Bennettitete 

 constitute an order distinct from and interme- 

 diate between the Cycadacese and the Coniferfe. 



Mr. Seward has devoted considerably more 

 than half his space to the Cycadacese in the 

 wider sense, and, although the number of forms 

 is not large, still the great difficulty that at- 

 tends the study of this class of material, as well 

 as the importance that such a study has, both 

 for biology and geology, fully justifies the 

 thoroughness of his treatment. In view of the 

 recent importance which the subject of cycadean 

 vegetation has assumed in America, this able 

 and excellent review of it by so competent an 

 authority as Tslr. Seward is in a high degree 

 timely and valuable. 



Although he gives the opinion of the leading 

 investigators, Carruthers, Solms-Laubach, etc., 

 to the effect that the Bennettitese cannot be 

 placed in the Cycadacese, still he does not him- 

 self make this distinction in the work before vis, 

 and treats all the forms that have been com- 

 monly referred to the Cycadacese under that 

 ordinal name. His subdivision is mainly into 

 Frondes, Tninci and F/ores, and in addition to 

 these he deals with several doubtful organs and 

 with numerous seeds (Carpolithes). 



One of the most valuable parts of the work is an 

 extended discussion of the fossil Cycadacese, oc- 

 cupying twenty pages. He first goes over the evi- 

 dence for the existence of this familj' in Paleozoic 

 beds, and the conclusion is decidedly in favor of 

 such a view, with, however, the qualification that 

 the Paleozoic Cycadacese are more or less syn- 

 thetic in their nature and possess marked re- 

 lationships with less highly developed groups 

 and especially with ferns. I know of no other 



place in which the proof of the Pteridophytic 

 ancestry of the Cycadacese in particular and of 

 the Gymnosperms in general has been so ably 

 marshaled. It constitutes another stejj in the 

 general march of botanical science towards the 

 breaking down of the barriers which formerly 

 so completely separated the Cryptogams from 

 the Phanerogams. Only those narrow system- 

 atists who are chiefly in search of differences, 

 and who so dread to encounter resemblances, 

 can regard this in any other light than that of 

 true scientific progress. 



Of the forms which are known only by their 

 fronds Mr. Seward recognizes six genera and 

 fourteen species in the English Wealden. The 

 genera are : Cycadites, Dioonites, Nilssonia, 

 Otozamites, Zamites and Anomozamites. Of 

 these Otozamites is represented by six species 

 and varieties, Cycadites, Dioonites and Zamites 

 by two each, while of Nilssonia and Anomo- 

 zamites only one species of each has been found 

 thus far. Four of these forms are described as 

 new, two of which, Cycadites Saportfe and Zam- 

 ites Ca7Tuthersi, have the rank of species, the 

 other two new forms being varieties of the old 

 species Otozamites Klipsteinii Dunk. , of the Ger- 

 man Wealden. The remainder of the fronds 

 are identified with species long since recognized 

 either by the earlier English or by Continental 

 authorities. 



Each of these genera and many of the species 

 are carefully discussed and a somewhat ex- 

 tended synonymy is appended. Numerous- 

 changes are also made, of which only one need 

 be mentioned, viz., the adoption of Schenk's 

 view of the form which has so long gone by the 

 name of Dioom^es Buchiaims (Ett.) Born., and 

 its reference to the genus Zamites. This has- 

 special interest for the American paleobotanist, 

 because it is one of the most abundant forms in 

 the oldest beds of the Potomac formation. This 

 form was first supposed (Goppert, 1S47) to be- 

 long to Pterophyllum, and its provisional refer- 

 ence to Dioonites by Bornemann in 1856 would 

 have received little attention had it not been 

 adopted by Schimper in his Traite de Paleon- 

 tologie Vegetale, and its reference to Miquel's 

 genus Dioonites has always been doubted by 

 some authors. The last change was that of 

 Xathorst, who, recoa;nizing its affinities witk 



