236 ME. HAMSHAW THOMAS OH THE FOSSIL FLORA OF [June 1913, 



venation. JSTo complete specimens are present in the collections- 

 here described, but the width of the fronds varies from 15 to 40 mm. 

 As usual, there is considerable variation in the number and in the 

 method of forking of the veins, but the distance between them never 

 seems to exceed more than *75 mm. The apex is seen to be refuse. 

 Some of the specimens are preserved in the grey shale ; and, of the 

 cuticles of these, excellent preparations have been obtained, which 

 show the following features. The stomata are found only on the 

 lower side, where they are very numerous and seem to be irre- 

 gularly scattered : they consist of two small brownish guard-cells, 

 slightly sunk below two large clearer lateral cells. The walls of 

 the epidermal cells exhibit a very sinuous outline, similar to that 

 seen in the fronds of Williamsonia and Dictyozamites. Numerous 

 irregular papilla? or hairs are seen on the lower epidermis. The 

 upper epidermis is composed of a homogeneous layer of cells with 

 rather thicker walls, presenting the same very sinuous outline. The 

 margins of some of the fronds are seen to be slightly crenulate. 

 The epidermal characters of these fronds agree closely with those 

 from Gristhorpe and Cloughton, but the latter seldom possess 

 papillae. 



Tceniopteris vittata has hitherto been usually regarded as the 

 frond of a fern ; but, owing to the form of the cuticle, I believe 

 that it is really the frond of a Bennettitalean plant. I hope to deal 

 more fully with this subject in a forthcoming paper. 



T-ENIOPTEKIS MAJOB Lindl. & Hutt. 

 [' Foss. Flor.' vol. ii (1833-35) pi. xcii.] 



Several specimens have now been found, of broad Tceniopteris-like* 

 fronds with a very coarse venation. The most complete example,, 

 from Mr. Saunders's collection, is about 15 cm. long, and repre- 

 sents the upper part of a frond. It is 5 cm. broad, and narrows 

 towards the apex, the tip being apparently rounded. The midrib is 

 narrow (1 mm.) ; the veins are somewhat crowded and numerous, 

 being given off at right angles to the midrib. They bifurcate once 

 or twice on their way to the margin. Other specimens collected by 

 the late Mr. Hawell, and now in the Middlesbrough Museum, show 

 portions of similar broad fronds. These are over 6 cm. broad, have 

 a narrow midrib (1 mm. or less), and lateral veins given off nearly 

 at right angles. The latter arise at intervals of 1 to 1-8 mm., and 

 bifurcate at varying distances from the midrib ; they are usually 

 twice bifurcated, and near the margin the ultimate divisions are 

 rather more than 05 mm. apart. 



These specimens may be compared with the figure of Tceniopteris 

 major given by Lindley & Hutton ; apparently they are sharply 

 marked off from the ordinary type of T. vittata by the breadth of 

 the lamina, and by the very coarse venation. By comparison with 

 other Yorkshire specimens, however, many transitional forms may 

 be observed ; and it may be that T. major ought only to be regarded 

 as a variety of the more abundant type. 



