MONOGRAPTUS. 



465 



etc. Lake District: Skelgill. Ireland: Coalpit Bay, Donaghadee. Wales : E. 

 side of Quarry, N.E. Fagwr-fawr, 2 miles E.N.E., Pont Erwyd; 8. side of Quarry, 

 270 yards N.E. Gwen-ffrwd Uchaf Farm. 



Associates, etc. — -Monog. Clingani occurs in some profusion in a band near the 

 top of the zone of M. convolutus, occurring - so plentifully in some localities as to 

 make the separation of the bed in which it is met with a matter of comparative 

 ease. It is commonly found with M. comma ids, M. convolutus, M. lobiferus, M. 

 decipiens, M. involutas, Orthog. bellulus, and Glimacog. scalaris. 



Collections.- — Geological Survey of Scotland, Geological Survey of England and 

 Wales, British Museum (Natural History), Sedgwick Museum, Belfast Natural 

 History Museum (Bullock Collection), Lap worth, and the Authors. 



Monograptus millepeda (M'Coy). Plate XLVI, figs. 10 a — d. 



1850. Graptolites millepeda, M'Coy, Ann. Mag. Nat. Hist. [2], vol. vi, p. 270. 



1854. Graptolites millepeda, Sedgwick and M'Coy, Brit. Pal. Rocks and Fossils, p. 5, pi. i b, fig. 6. 



1876. Monograptus lobiferus, Lapworth, Geol. Mag. [2], vol. iii, p. 499, pi. xx, fig. 1 c. 



1892. Monograptus lobiferus, Tornquist, Siljansomrad. Grapt., ii, p. 18, pi. i, fig. 36, pi. ii, fig. 4. 



Figs. 323 a — c— Monograptus millepeda 



(M'Coy). 



m 



Polypary several cm. in length, arcuate, with abruptly involute proximal 



portion, widening rapidly to a maximum 

 breadth of 1'5 mm., which is then approxi- 

 mately constant. Thecse on the convex 

 margin, fourteen to ten in 10 mm., of the 

 general type of those of M. lobiferus, but 

 with rather less of the theca involved in the 

 lobation, and with a rather less tightly coiled 

 lobe. 

 Description. — The polypary is always strongly 

 curved, and in the proximal portion is conspicuously 

 involute, after the manner of M. cyphus, but some- 

 what more abruptly. It widens quickly from an 

 initial breadth of about - 5 mm. to a maximum of 

 1*5 mm. 



The sicula has a length of fully 1 mm. 



The thecee face obliquely inwards, and from 



specimens preserved in relief it is clear that there 



was considerable torsion of the whole apertural 



region ; the fraction of the theca involved in the 



formation of the lobe never exceeds one-half of its 



total length, and occupies about five-sevenths of the total breadth of the polypary. 



Affinities. — Monog. millepeda has occasionally been confused with M. lobiferus or 





a. Proximal portion with sicula, in low 



relief. Rheidol Gorge, 440 yards 

 S.S.E. of Bryn-chwith,Pont Erwyd. 

 Geol. Survey England and Wales. 



b. Proximal theca; in partial relief. 



Llanystwmdwy, near Criccieth. Coll. 

 Fearnsides. 



c. Distal thecal. Parys Mount, Angle- 



sea. Geol. Survey of England and 

 Wales. 



