MONOGRAPTUS. 



4G1 



Horizon ami Localities. — Gala-Tarannon Beds (zones of M. turriculatus, M. 

 crispus, M. griestoniensis). 



Luke District : Swindale. Wales : Forge Corner, Conway; Afon Gyffin opposite 

 Conway Castle; Llanystwmdwy, near Criccieth ; Tarannon River; Afon Cwm 

 Calch, Talerddig. 8. Scotland: Belcraig Burn; Clanyard Bay, near Drumtnore, 

 Mull of Galloway; Darnick Bridge, near Melrose. 



Associates, etc. — Monog. dextrorsus is fairly abundant in a fragmentary condition 

 in the Lower Gala beds (Tarannon) associated with M. Marri, M. exiguus, etc., in the 

 zone of M. crispns; it occurs also in the preceding zone with M. Halli, M. runcinatus, 

 M. iiudus and Bastrifes maximus, and at the top of the succeeding zone of M. 

 griestoniensis with the zone fossil, M. discus and M. priodon. 



Collections. — Sedgwick Museum, Geological Survey of Scotland, Lapworth, and 

 the Authors. 



Monograptus remotus, sp. nov. Plate XLVI, figs. 9 a, ti 



Polypary slender, arcuate, of unknown length, widening very gradually from 

 the initial reo-ion to a maximum breadth of "6 mm., which is thereafter 

 approximately maintained. Thecas on the convex margin, three to four in 

 10 mm., becoming increasingly remote distally ; slender, of the general type 

 of those of M. lobiferus, but far longer, and with only the extreme apertural 

 region involved in the lobe ; overlap insignificant. 



Description. — The polypary is arcuate, with the 



Fia. 319. — Monograptus remotus, sp. 

 nov. 



thecag on the convex margin. The maximum 



breadth is only attained opposite the lobate apertural 

 region of the thecge ; elsewhere it does not exceed 

 "3 mm. and is uniform, the ventral walls of succes- 

 sive thecas forming a straight line which is only 

 broken by the projecting lobes. 



The thecas are very long uniformly narrow tubes, 

 with only the extreme apertural region coiled up to 

 form the lobe ; these lobes are very remote from 

 each other, and their remoteness increases distally, 

 which is (so far as is known at present) a unique 

 character among Graptoloidea. 



Affinities. — The long thecas of Monog. remotus 

 with their remote apertural lobes appear to be so 

 peculiar as to enable the polypary to be recognised 



with ease. The thecas are somewhat similar to those of M. Barrandei but far more 



remote, while the curvature of the polypary is different. 



Enlargement of part of PI. XLVI, fig. 

 9 6, showiiio- the characteristic in- 

 crease in the length of successive 

 thecas. 



