MONOGRAPHS. 457 



show more conspicuous torsion than do those of the proximal portion, and, in 

 addition, they are more closely set, measuring nine in 10 nun. as compared with 

 seven in the proximal part. 



Affinities. — The form of the polypary, its rapid increase in breadth, and the 

 strongly lobed theca? render the species unique amongst the Monograpti. 



Horizon and Localities. — Gala-Tarannon Beds (zone of M. crispus). 



S. Scotland: Meigle Quarry, Galashiels ; Gala Hill; Grieston Burn ; Caddon- 

 foot ; Canldshields, etc. Wales : Tarannon Kiver ; Gelli Stream, near Llanbryn- 

 mair ; South of Llwyn-ffynon, etc. ; Forge Corner, Conway, hake District : Great 

 Rundle Beck. Ireland : Portaferry ; Tieveshilly. 



Associates, etc. — Moitoij. crispus is fairly common in, and restricted to, the zone 

 of M. crispus, associated with M. discus, M. exiguus, M. Marri. 



Collections. — Belfast Natural History Museum, Sedgwick Museum, Black, 

 Lapworth, and the Authors. 



Monograptus flagellaris, Tornquist. Plate XLVI, fig. '■). 



1892. Monograptus flagellaris, Tornquist, Siljansomrad. G-rapt., ii, p. 42. pi. iii, figs. 31-33. 



Polypary small, of conical spiral form, with the theca? first on the convex and 

 then on the concave margin, increasing rapidly in breadth to a maximum of 

 1 mm. Theca? twelve in 10 mm., almost sub triangular, with apertnral 

 region bent into a closely-coiled and twisted lobe, which occupies about 

 seven-tenths of the total breadth of the polypary. 



Description .—The twisted form of the polypary, which is invariable, seems to 



be characteristic of this species, which never exceeds 



Fig. 315. — Monogravtus flagellaris, <-» • i ,i -i • • -n • i i,i 



Tornquist. * cm - m length, and increases rapidly in breadth 



throughout that distance. 



The theca? are of the same type throughout, 

 though the lobate character of the apertnral region 

 becomes steadily more pronounced towards the distal 

 end. The torsion of the thecal axis is indicated in 

 the front view and becomes even more obvious when 

 the polypary is viewed from the back, when scarcely 

 any indication of the lobe is seen. 



Affinities. — The rapidly widening polypary, its 

 peculiar form, and the characteristic theca? are 



Enlargement of PI. XLVI, fig. 3. . 



together sufficient to make the identification of 

 Monotj. flagellaris comparatively easy. There is, however, an obvious approxi- 

 mation as regards the shape of the theca? to the members of the M. con rot ut us 

 Group. 



