White — New Fossil Plant from Bahia, Brazil. 635 



lineate, and deeply depressed, so that it is considerably below 

 the plane of the ventral surface of the pinnules. The latter 

 vary in position from opposite to alternate, and are distinctly 

 Alethopteroid in form and arrangement, being connivent at 

 the base, open nearly at right angles to the rachis, and strongly 

 convex ventrally on either side of the very thick midrib, which 

 is persistent, vanishing very abruptly just before reaching the 

 apex. In some of the fragments the pinnules appear to be 

 hardlv decurrent, the midrib originating at nearly a right angle 

 with the rachis. Likewise in the large fragment there is verv 

 little indication of decurrence in the lamina bordering the 

 rachis between the pinnules, but in the small fragment on the 

 upper right in fig. 2, the typical decurrent Alethopteroid wing 

 and the downward direction of the sinus may be observed. 



On account of the density of the coaly residue and the degree 

 of maceration undergone by the lamina it is difficult satisfac- 

 torily to describe the nervation which may be seen in the impres- 

 sions of the pinnules. The nerves originate for the most part 

 slightly oblique to the midrib or rachis, though in many cases 

 they appear to emerge at right angles to the latter. They are 

 in general close and nearly parallel, usually forking near the 

 base, one of the divisions being rarely forked, though a large 

 number of the nerves appear to run simple from the midrib 

 nearly straight to the margin, which they meet slightly ob- 

 liquely or nearly at a right angle. When examined closely 

 under the lens the nervation of many of the pinnules is found 

 to have the aspect of being polygonally meshed throughout a 

 narrow zone near the midrib. At certain other points where 

 the preservation is apparently better, as shown in fig. 3, the 

 nerves appear to be straighter, more nearly parallel, without 

 anastomosis. It is almost certain that they do not anastomose, 

 though occasional meshing is possibly present. The aspect 

 of meshing may be due to maceration of the lamina, in which 

 the mesophyll was apparently thick and the epidermis proba- 

 bly coriaceous. 



For the reasons above explained I am disposed provisionally 

 to regard the nerves as probably entirely free rather than 

 in part anastomosed near the midrib, and, therefore, I tenta- 

 tively refer the plant to the genus Alethopteris, a strictly arti- 

 ficial or form-genus of Cycadofilices, with which the Brazilian 

 fragments in other respects fully agree. The species is named 

 Alethqpteris Branneri, in honor of the donor, who, in coop- 

 eration with Dr. Derby, the Director of the Brazilian Geologi- 

 cal Survey, has contributed so largely to our knowledge of the 

 geology of Brazil. 



The agreement of the Brazilian fragments, so far as concerns 

 their general aspect, with several species of Aethopteris is at 



