Dr. H. A. Nicholson on new Sj^eci'es of Graptoh'tes. 241 



curved. The celkiles are about eighteen in the space of an 

 inch, and are indistinguishable in all their characters from 

 those of G. Nilssoni, Barr. They are long, narrow, and so 

 arranged that they do not overlap one another at all ; the outer 

 cell-walls being inclined to the axis at an angle of not more 

 than 15° to 20°, and being three to four times as long as the 

 cell-mouths, the latter forming short transverse apertures at 

 right angles to the axis. 



This pretty little species is readily separated from all allied 

 forms (such as JD. nitidus, Hall, and D. serratulus, Hall) by 

 the remote free cellules, which do not overlap one another, by 

 the general shape of the frond, and by the small length and 

 great tenuity of the stipes. 



Loc. Lower beds of the Skiddaw Slates, BarfF, near Kes- 

 wick. Upper beds of the Skiddaw Slates, Ellergill, near Mil- 

 burn ; and Eggbeck, near Pooley. 



Dtdj/mograjysusfascicidatus, Nicli. PI. XI. figs. 21 & 22. 



Spec. char. Frond consisting of two simple stipes arising 

 from a short obtuse radicle. The stipes are at first directed 

 horizontally outwards, but are immediately bent downwards 

 towards the radicle, again curving horizontally outwards. 

 The cellules occupy the concave face of each stipe, forming 

 thus the angle of divergence ; but, owing to the curvature of 

 the stipes, the amount of this angle can hardly be stated. 

 Each stipe is extremely narrow at first, but gradually widens 

 out till a breadth of nearly one twenty-fourth of an inch may 

 be reached. The common canal is very narrow, but is wider 

 than the cellules. The cellules are excessively long and nar- 

 row, curved, following the curvature of the stipe, the cell- 

 mouths being at right angles to the axis of the cellules. The 

 cell-mouths are not more than about twenty-four in the space of 

 an inch in the adult portion of the stipe, and the cellules overlap 

 one another for fully two-thirds of their entire length. An indi- 

 vidual cellule, when fully grown, may have the extraordinary 

 length of more than two lines, with a uniform breadth of not 

 more than one-hundredth of an inch. Owing to the great 

 length and narrowness of the cellules, and owing to their 

 inclination being so small that they are nearly parallel to the 

 back of the stipe, the cellules in the distal portion of the stipe 

 appear to form a bundle of long narrow tubes. In consequence 

 of this, a line drawn at right angles to the distal portion of the 

 stipe would exhibit a section of three, or even four, cellules. 



This species cannot be confounded with any other, being 

 distinguished by the curiously curved stipes with the cellules 

 on their concave aspect, the latter being nearly parallel to the 



