Dr. H. A. Nicholson on new Sjjecies of GrajotoUtes. 235 



All the specimens wliich I liave of this species are derived 

 from the upper beds of tlie Skiddaw Slates, and are Loth poitrly 

 preserved and a good deal distorted by cleavage. The great 

 remoteness of the cellules, however, and the extraordinary 

 length of their spiny appendages are characters which distin- 

 guish this from all other forms. 



Loc. Upper beds of the Skiddaw Slates, Thornship Beck, 

 near Shap, 



Dijjiograpsus Hughest, Nich. PL XI. fi^^s. 9 & 10. 



Spec. char. Frond diprionidian, about one quarter of an inch 

 in length, and one-sixteenth of an inch in width in the fully 

 developed portion. Base obtusely pointed, apj^arently Avithout 

 any proximal extension of tlie solid axis. Frond forming a 

 cylindrical tube, which is divided into two vertical compart- 

 ments by a longitudinal septum. This septum, in all the 

 Diplograpsi with which I am acquainted, is perfectly straiglit 

 or is very slightly undulated ; and its lateral margins appear 

 on the exterior of the test as very slightly wavy or straight 

 lines between the rows of cellules. In the present species, 

 liowever, the septum must be strongly and sharply bent first 

 to one side and then to the other, since the impressed line on 

 the exterior (which may conveniently be called the "suture") 

 is regularly and strongly bent from side to side so as to be 

 almost zigzag. The common canal is excessively nan-ow. 

 The base of each cellule is apjdied to a concavity of the undu- 

 lating septum, so that a regular alternation is maintained on 

 the two sides of the frond. The cellules are about thirty in 

 the space of an inch, overlapping one another not at all or for 

 an extremely short distance, curved, nearly vertical (or parallel 

 to the axis of the frond), their outer margins sti'ongly convex ; 

 the cell-mouths horizontal (or at right angles to the axis of the 

 frond). The test is perfectly smooth. 



This extraordinary species reminds us of Z>. /rtw«r/scMs,Xich., 

 in the characters of the curved, cup-sliaped, vertical cellules, 

 with their horizontal cell-mouths and extremely narrow com- 

 mon canal. It is easily distinguished, however, by the imdu- 

 latcd (not straight) suture, and by the constant absence of the 

 beautifid transverse stria? which are so characteristic of all 

 examples of D. taman'scns which are preserved in relief. I 

 have named the species after my friend Mr. Hughes, of the 

 Geological Survey. 



Loc. Graptolitic mudstones of the Coniston series, Skelgill 

 Beck, near Ambleside. (Beautifully preserved in relief.) 



Diplograjisits simiatns^ Nich. PL XI. fig. 11. 

 Spec, cliar. Frond diprionidian, from four to five lines in 



