Carruthers — On British Graptolites, 129 



posed of a flexible substance, that I doubt if specific characters of value can be 

 deduced from them. 



4. n. sextans, M'Coy (Pal. Foss. p. 9). G. sextans^ Hall (Pal. of N. York, 

 vol. i., p. 273, pi. Ixxiv., fig. 3). Loc. Moffat. 



5. D. Forchhanwiei'i, Baily (Grapt. of Meath, etc., p. 6, fig. 7). Cladograpsits 

 Forchhammeri, Gein. (Die Grapt., p. 31, pi. v. figs. 28-31). Branches of poly- 

 pary slender, divaricating in straight lines, and at a vv^ide angle, bent backwards 

 towards the initial point. Ilydrothecce not very marked, in contact throughout 

 almost their whole length ; about 28 in an inch. Initial process permanent : 

 the two first cells developed at a right angle to it, their mouths furnished each with 

 a very fine short spine ; a third similar spine proceeds from between the bases of 

 the two primary cells opposite to the initial process. Loc. Moffat, and Kilnacreagh, 

 Co. Clare. 



6. D. elegans^s^. nov. (PI. V., Fig. ^,abc). Branches of the polypary divarica- 

 ting at various angles, and with a slight curve within a short distance of the 

 proximal origin of the polypary. The hydrothecoe are rounded at the apex, and 

 free throughout a considerable portion of their length, and the intervening spaces 

 are rounded at the base ; about 22 cells in an inch. The initial process is obvious 

 in young specimens, but I have not been able to detect it in old individuals ; the 

 outer apex of the angle ornamented with 3 short strong spines. Loc. Moffat. 



Dr. Nicholson has enabled me to refer his D. flaccidns (Geol. Mag., Vol. IV., 

 p. no, PI. VII., Figs. 1-3) to this species. His fig. i has a general resemblance to 

 Hall's G. flaccidns, but the form and number of the cells and the breadth of the 

 polypary are very different. In Hall's species there are "from 28 to 30 and near 

 the base sometimes 31 " cells in the space of an inch. In Dr. Nicholson's drawing, 

 " nat. size," there are 14 ! The figs. 2 and 3 made me fancy that he might mean 

 the species I have just described, but it would have been impossible, except on his 

 own authority, to have settled the matter. Loc. Moffat. 



7. D. Moffatensis, Carr. (Trans. R. Phys. Soc. Edin., 1858, p. 469, fig. 3). 

 G. divaricatus. Hall (Pal. N. York, vol. iii. pt. i, p. 514, 1859). D. anceps^ 

 Nicholson (Geol. Mag., Vol. IV., p. no, PI. VIL, Figs. 18-20). The last 

 paragraph in Dr. Nicholson's description of this species shows that he had over- 

 looked D. Moffatensis when he wrote it, and his comparison of his fossil with 

 Hall's figure puts it beyond a doubt that I have rightly placed D. anceps here as 

 a synonym. Loc. Moffat. 



8. D. caduceiis. Salt. (Quart. Journ. vol. xix., p. 137, fig. 13). G. Bigsbyi^ HaU 

 (Grapt. Quebec Gr. p. 86). Hall has to my mind clearly shown this to have four 

 branches. Loc. Skiddaw Slates. 



9. D. bryonoides. — Tetragrapsns bryonoides, Salt. (Quart. Journ., vol. xix., 

 P- 137* fig- ^^)- <^- bryonoides, Hall (Grapt. Quebec Gr. p. 84). Loc. Skiddaw 

 Slates. 



10. D. quadribrac hiatus — G. quadribrachiatus^ Hall (Geol. Surv. of Canada, 

 Rep. 1857, p. 125). 'x etragrapsus crucialisy Salt. (Quart. Journ., vol. xix., p. 137, 

 fig. %b). Loc. Skiddaw Slates. 



Gen. V. — DicHOGRAPSus, Salt. (The Geologist, iv., p. 74). Poly- 

 pary compound, growing bilaterally, and branching more or less 

 frequently in a dichotomous manner, the hydrocaulus, or non-celluli- 

 ferous bases of the branches invested with a corneous disc. 



Sp. I. D. octobrachiatus, — G. octobrachiatus. Hall (Canada Rep. 1857, p. 122 ; 

 Grapt. Queb. Gr. p. 96, pi. 7, 8), D. aranea^ Salt. (Quart. Journ. xix., p. 137, 

 fig. 9). Loc. Skiddaw Slates. 



2. Z). Sedgwickii, Salt. (Quart. Journ. xix. p. 137, fig. ii). Loc. Skiddaw Slates. 



Gen. VI. — Cladograpsus, Carr. (Trans. E. Phys. Soc. Edin., 1858, 

 p. 467). Polypary compound, growing bilaterally from the primary- 

 point irregularly, and repeatedly branching and rebranching, and 

 without a central disc. Pleurograpsus, Nicholson (Geol. Mag., Vol. 

 IV., p. 256). 



Sp. I. C. linearis, Carr. (Trans. R. Phys. Soc. Edin., 1858, p. 467, fig. i). 

 Plmrograpsus linearis^ Nich. (1. c. ) This species has a slender polypary, and cells 



