PLATE XXI. 

 Dicellograptus— (con filmed) . 



FIGS. 



1 a — e. — Dicellograptus sextans, Hall. (Page 153.) 



1 a. Type specimen of Hopkinson's Dicranograptus formosus, G-eol. 



Mag., 1870, vol. vii, pi. xvi, figs. 2 b, 2 r, 2 d. Belcraig Burn. 



Glenkiln Shales. Sedgwick Museum. 

 1 6. Ibid. Fig. 2 a. 

 1 c. More widely divergent form. Belcraig Burn. Glenkiln Shales. 



Lapworth's Collection. 

 Id. Typical form. Belcraig Burn. Glenkiln Shales. Wood's Collection. 



1 e. Ditto. Lapworth's Collection. 



2 a — d. — Dicellograptus sextans, var. exilis, Biles and Wood, nov. (Page 155.) 



2 a. Typical form. Dobb's Linn, Moffat. Upper Glenkiln Shales. 



Wood's Collection. 

 2 b. Ditto. Birnock, S. Scotland. Glenkiln Shales. Lapworth's 



Collection. 

 2 c. Ditto. Wandel Water, Abington. Glenkiln Shales. Geological 



Survey of Scotland, Edinburgh Museum. 



2 d. Ditto. On same slab as fig. 2 c. 



3 a — /. — Dicellograptus pumilus, Lapworth. (Page 149.) 



3 a. Large typical specimen. Hartfell Spa. 11 art fell Shales. Lapworth's 



Collection. 

 3 b. Imperfect specimen, but with typical form of axil. Hartfell Spa, 



Hartfell Shales. Lapworth's Collection. 

 3 c. Well-preserved specimen showing sicula. Ibid. 

 3 d. Incomplete sjjecimen. Ibid. 

 3 e. Specimen showing sicula. Ibid. 

 3/. Ditto. Conway Railway Cutting, N. Wales. Hartfell Shales. 



Lapworth's Collection. 

 4. — Dicellograptus angulatus, Elles and Wood, sp. nov. (Page 149.) 



4. Portion of slab with examples showing typical habit. Morroch 



Bay. Upper Glenkiln to Lower Hartfell Shales. Geological 



Survey of Scotlaand, Edinburgh Museum. 



5 a — c — Dicellograptus patulosus, Lapworth. (Page 147.) 



~> a. Typical form. Craigmichan Scaurs. Glenkiln Shales. Lapworth's 



Collection. 

 5 b. Typical form with long sicula. Same slab as fig. 5 a. 

 ■) c Somewhat more slender form. Builth. Glenkiln Shales. Lapworth's 



Collection. 

 5 d. Specimen widened by compression, showing prominent " initial " 



and " lateral " spines. Belcraig Burn. Glenkiln Shales. 



Wood's Collection. 



5 e. Slender specimen. Glenkiln Burn. Glenkiln Shales. Lapworth's 



Collection. 



6 a—d. — Dicellograptus Morrisi, Hopkinson. (Page 155.) 



6 a. Young specimen, doubtfully referable to this species. Figured, 



Hopkinson, Geol. Mag., 1871, vol. viii, pi. i, fig. 2 e. Dobb's 

 Linn. Hartfell Shales. Sedgwick Museum. 



6 b. Typical form. Glenkiln Burn. Hartfell Shales. Lapworth's 

 Collection. 



6 c. Ditto. Dobb's Linn. Hartfell Shales. Lapworth's Collection. 



6 d. Ditto. Hartfell Spa, Wood's Collection. 



