-W8 BRITISH GRAPTOLITES. 



whole (M. capillaeeus), while in others the lobe is by far the most conspicuous 

 feature, and an adnate (or overlapped) region of the theca appears to be almost 

 wanting, or at all events is relatively insignificant (M. lob if er us, M. Barmndei). 



In this group the appearances resulting from the direction of compression and 

 the state of preservation are even more varied and pronounced than in the group 

 of M. priodon, owing to the greater degree of torsion of the theca. Here, as in all 

 forms of Monograptidse, there would seem to be four more or less distinct right- 

 hand views, and four more or less distinct corresponding left-hand views according 

 as to whether the theca is preserved (a) in full relief, (h) half relief, (c) split down 

 the centre, or (</) partly split and partly in relief. 



In this group the theose are uniform in type throughout and all the polyparies 

 are curved. They may be sub-divided as follows : 



(a) The polypary has dor si- ventral curvature. Type Monograptus lobiferus. 

 M. runcinatus, var. pertinax, M. Beclci, M. exigitus, M. nodifer, M. erispus, 

 M. flagellaris, M. capillaeeus, M. retrojlexus, M. dextrorsus, M. remotus (?). 

 (li) The polypary has ventral curvature (?). 



M. Itarrandei, M. Icnockensis. 

 {<■) The polypary has dorsal curvature. Type Monograptus Cling ani. 

 M. millepeda. 



V (a) : Monograpti with lobed theca? in which the polypary has dorsi-ventral 



curvature. 



Monograptus lobiferus (M'Coy). Plate XLV, figs. 1 a—f 



1850. Graptolites lobiferus, M'Coj, Aim. Mag. Nat. Hist. [2], vol. vi, p. 270. 



1851. Graptolites Becki, Harkness, Quart. Journ Greol. Soc, vol. vii, p. 60, pi. i, fig. 6. 

 1851. Graptolites Nicoli, Harkness, Quai't. Jouru. Greol. Soc, vol. vii, p. 61, pi. i, fig. 5. 

 1855. Graptolites lobiferus, M'Coy, Brit. Pal. Foss., p. 4, pi. i b, fig. 3. 



1868. Graptolites lobiferus, Nicholson, Quart. Journ. Geol. Soc, vol. xxiv, p. 532, pi. xxx, fig. 30. 



1876. Monograptus lobiferus, Lapworth, Geol. Mag. [2], vol. iii, p. 26, pi. xx, figs. 1 a, b, d. 



1892. Monograptus lobiferus, Tornquist, Siljansomrad. Grapt., ii, p. 18, pi. i, fig. 37 ; pi ii, figs. 1, 



2,3. 



1899. Monograptus harpago, Tornquist, Monog. of Scanian Bastrites Beds, p. 16, pi. iii, figs. 3-11. 



Polypary slender, flexed or straight, several cm. in length, widening fairly 

 quickly from an initial breadth of about "2 mm. to a maximum of about 

 '2 7iim. which is then maintained. Thecse ten to seven in 10 mm., 

 with fully three-quarters of the thecal length involved in the conspicuous 

 lobe which occupies about three-quarters of the total breadth of the polypary. 

 Overlap insignificant. 



Description. — The polypary must often have attained a great length, for frag- 



