130 Carruthers — On British Graptolites, 



so slightly elevated as not to be clearly seen without the aid of a lens ; there are 

 about i8 to the inch. Dr. Nicholson's figure, " nat. size," represents a strong 

 polypary with well-marked cells, and from 6 to 9 in an inch ! I have no doubt 

 that it was drawn as Dr, Nicholson says for this species, but it is greatly to be re- 

 gretted that such drawings are published ; they can serve only to increase the dif- 

 ficulties that under the most favourable circumstances beset every scientific investi- 

 gation. Loc. Moffat. 



2. C. capillaris, sp. nov. (PI. V., Fig. 7 a, b) Extremely slender polypary, 

 with remote branches, and very minute hydvothecse ; about 24 in an inch. It is 

 not so abundant as C. linearis, and is very easily distinguished by its capillary ap- 

 pearance. It is probably the same species as that figured and described by 

 Emmons in his American Geology, vol. i., p. 109, pi. I, fig. 7, under the name of 

 N'emagrapsus capillar is. Loc. Moffat. 



3. C. gracilis, — G. gracilis, Hall (Pal. N. York, i. p. 274, pi. Ixxiv, fig. 9); 

 Rastrites Barjandei, Harkn. Loc. Moffat, and Bellewston Hill, Meath. 



Gen. VII. — Dendeograptus, Hall (Grapt. Quebec Gr. p. 126). 

 Polypary compound, with a thick common hydrocaulus giving off 

 branches irregularly, which repeatedly subdivide in a dichotomous 

 manner. 



Sp. I. D.furcatulus, Salt. (Mem. Geol. Surv. iii., pi. il. a, fig. 5). 



2. D. lenfus, Carr. (Murch. Sil., Ed. iv., p. 541, fig. 5). Branches of the poly- 

 pary repeatedly dichotomising ; hydrothecse acute-angular, about 18 in the inch. 

 This is a much more robust species than that described by Salter. I have seen no 

 more of it than the well-marked specimen figured (PI. V., Fig. 5). Loc. Fer- 

 managh. 



Gen. VIII. Diplograpsus, M'Coy (Pal. Toss., p. 7). Polypary 

 with a double series of cells on either side of a slender axis. Hydro- 

 thecee distinct from the periderm of the common canal. 



Sp. I. D. pristis, His. (Leth. Suec. p. 114, pi. xxxv. fig. 5), D. foliaceus, Murch. 

 (Sil. Syst.) Fucoides deniatus, Brongn. (Hist. Veg. Foss. I. p. 70). D.physophora 

 Nich. (Ann. Mag. Nat. Hist., January, 1868, p. 56). Z>. vesiciilos7is, Nich. (ibid 

 P- 57)- This is the best known and most abundant species of JDiplograpsus. 

 Although it has been frequently figured I have had four specimens drawn on PI. 

 v., with the view of illustrating the different forms of the appendages at the 

 proximal end. The species generally appears as if it terminated in an acute point, 

 formed by the approximation of the two primal cells ; occasionally a spine con- 

 tinuing the line of the axis, and two lateral ones, are found (13 b, c, d), and in one 

 specimen (13 «) I have observed two long slender processes rising together from 

 the proximal points of the polypary, and produced apparently by the abnormal 

 division of the medial spine. The axis is generally prolonged at the distal end, 

 and is sometimes twisted and enlarged as described by Barrande (Grapt. deBoh. p. 

 4), and figured in different species of Diplograpsus by Barrande, Geinitz, Baily, 

 etc. Dr. Nicholson has founded his D. vesiadosus on a specimen with the axis in this 

 condition, and Z>. physophora is evidently another specimen of the same species 

 in accidental contact with a " grapto-gonophore, " or some other body. Loc. 

 Moffat, etc. 



2. D. minntiis, sp. nov. (PI. V., Fig. 12, a, b). This agrees with Z>. pristis in 

 general appearance, and in the form and arrangement of the cells, except that the 

 whole polypary and all its parts are so very small. Had I met with only a few 

 specimens, I would have considered it as merely an accidental variety, but I have 

 seen so many, all agreeing in size, that I cannot doubt that it is a good species, 

 especially as young specimens of D. pristis early attain their full breadth, and the 

 increase of the polypary is by additions to its distal end, and not to the size of the 

 already formed hydrothecDS, just as in the living Sertidariadce. About 38 cells to 

 one inch. Loc. Moffat. 



3. D. ajigustifolitcs, Hall (Pal. N. York HI., p. 515, figs, i and 2). D. acumi- 

 natus, Nich. (Geol. Mag., IV., p. 109, PI. VII., Figs. 16 and 17). Loc. Moflfat. 



4. D. persculptus (Cat. Foss. Mus. Pract. Geol. p. 25). Beautiful specimens of 

 this species, which I recently saw in the Woodwardian Museum, Cambridge, 

 convinced me of its distinctness. It is nearly allied to D, pristis and D. folium. 



