1852.] SALTER ON GRAPTOLITES. 389 



G. ludensis, therefore, only remains, as quoted by me in the list 

 given in Prof. Nicol's paper*. It is accompanied however by another 

 species, apparently an undescribed form, with cells closely set, each 

 with a long decurved spine from its upper edge. I have called it 

 Cr. Flemingiiy and figures and a description are subjoined. 



DiPLOGRAPSUs TERETiuscuLus, Hisingcr, sp. PI. XXI. figs. 3, 4. 



Prionotus teretiusculus, Hisinger, Lethsea Suecica, Supp. 2 (1840), 

 p. 5. t. 38. f. 4. 



6r. teretiusculus, Scharenberg (1851), Ueber Graptol. t. 2. f. 17-32. 



G. personatus, Scharenberg, ibid. t. 1. f. 12. 



G. teretiusculusy Geinitz (1852), Verstein, Grauwack. Sachs, heft i. 

 p. 26. 



Spec. Char. Cylindricus aut subcompressus, insuper et subter linea mediana 

 recta vel subundulata exaratus ; cellularum oribus transverse oblongo-ovalibus, 

 diametruni suum verticalem sese distantibus, simplicibus, nee ad marginem 

 inferiorem prominulis, subtus in lineam impressam brevem utrinque exce- 

 dentibus. 



Cylindrical, rather quickly tapering at the small end, smooth, 

 marked down the upper and lower side by an impressed median line, 

 which is generally straight, but sometimes a little wavy between the 

 two rows of cells. The mouths of the cells are transverse, oval-ob- 

 long, a little curved down on each side so as to be obscurely lunate, 

 their edges not at all projecting from the general surface ; they are 

 placed nearly their own breadth apart from one another in the full- 

 grown part, and there appear to occupy the whole width of the tube 

 (in the young part they are smaller and more distant proportionally) . 

 From the base of the mouth on each side a short impressed line 

 extends downward, but not so far as to the succeeding cell-mouth, 

 and either parallel to the median line or very slightly inclined towards 

 it. The surface shows transverse lines on all parts. 



We have compared this well-marked species with excellent speci- 

 mens, from the alum slate of Scandinavia, in the collection of the 

 Geological Society. Hisinger' s figure is a very bad one. 



The axis of this species, as in G. hicornis. Hall, and some others of 

 the same group, is narrower than the general thickness, so as in this 

 case to be visible only as a longitudinal constriction or impressed line. 



This Graptolite, like the D. rectangularis, M'Coy, which very 

 possibly may also belong to the species we are describing, is re- 

 markable for having the cell-mouths simply excavated in the sides, — 

 the lower edge not at all projecting as it does in all the other folia- 

 ceous Graptolites ; indeed, in this species the openings are a little sunk 

 beneath the general surface, so as to render the interspaces somewhat 

 tumid. 



Locality. Glenkiln, Dumfriesshire. The species occurs also in 

 Anglesea, N. Wales, in considerable perfection. 



* Quart. Journ. Geol. See. vol. vi. p. 54 & 64. 



