236 Dr. H. A. Nicholson on neio Species of Graptolites. 



length, and one line in breadth in the fnlly developed portion. 

 Base pointed, and furnished A\dth a long straight radicle. 

 Cellules from thirty-six to forty-five in the space of an inch, 

 forming an angle of about 40° with the axis, and overlapping 

 one another for more than two-thirds of their entire length. 

 In shape the cellules are somewhat curved, wide at the base, 

 contracted in the middle of their length, and expanding into 

 rounded knobs towards the cell-mouths. 



This species is only known to me by some two or three 

 specimens, in a state of high relief, from the mudstones of the 

 Coniston series. The characteristic of the species is the pecu- 

 liar sinuous outline of the cellules, produced by the undulating 

 cell-jjartitions. 



Log. Graptolitic mudstones of the Coniston series, Skelgill 

 Beck, near Ambleside. 



Di]}logrwpsus himucronatuSj Nicli. PI. XI. figs. 12 & 12'. 



Sjyec. char. Frond diprionidian, from one to two inches in 

 length, and attaining in the fully-grown portion of large spe- 

 cimens a width of over two lines, exclusive of the spines from 

 the cell-mouths. Base obtusely pointed. Cellules from twenty- 

 eight to thirty in the space of an inch, broad at the base and 

 gradually tapering towards the cell-mouths, so as to form long 

 extended denticles, the upper margins of which are nearly 

 straight and are at right angles to the axis, whilst tlie inferior 

 margins are curved and form an angle of about 45° with the 

 axis. The extremity of each denticle is furnished Avith two 

 long flexible spines, which are usually bent downwards, and 

 sometimes attain the extraordinary length of more than one 

 line and a half 5 so that the breadth of the entire frond, in- 

 cluding the spines, may be as much as a quarter of an inch. 

 The spines increase regularly in length as the distal extremity 

 of the frond is approached. 



In the general shape of the cellules, D. himucronatus closely 

 resembles D. viucronatus. Hall, from Avhich it is distinguished 

 by the much greater size of the frond and by the possession of 

 two spines proceeding from the extremity of each denticle, the 

 latter species possessing but one spine, and that a smaller one, 

 to each cellule. ,From D. quaclnmucronatus, Hall, in which 

 each cellule has two sj)ines, our species is readily separated by 

 the characters of the cellules. 



Loc. Not uncommon in a single bed of anthracitic shale, 

 Glenkiln Burn, Dumfriesshire. 



Diplograijsus insectiformis^ Nich. PL XI. fig. 13. 

 Sjpec. cliar. Frond diprionidian, not exceeding two and a half 



