456 



BRITISH GRAPTOLITES. 



Conway; Bank of Afon Gyffin, opposite Conway Castle; Llanystwmdwy ; Cefn 

 Hendre Quarry, about 1-50 yds. E. of Farm, 1\ miles E. of Aberystwyth. 



Associate*, etc. — Monog. nodifer is not a very abundant fossil in Britain, but 

 it has been found at the base of the Gala beds associated with M. turrinulatus, M. 

 iindax, M. rirnciiiiitiix, and Rastrites maximus, and also at a higher horizon with M. 

 exiguus and M. crisp us. 



Collections. — Geological Survey of England and Wales, Sedgwick Museum, 

 Fearnsides, Lapworth, and the Authors. 



Monograptus crispus, Lapworth. Plate XLV, figs. 6 a — f. 



1876. Monograptus crispus, Lapworth, Geol. Mag. [2], vol. iii, p. 50-?, pi. xx, tig. 7. 

 1907. Monograptus gemmatus, Tornquist, Rastrites and allied species of Monograptus, Lund. Univ. 

 Arsskr., n.s., afd. 2, iii, no. 5, p. 21, pi. iii, figs. 26, 27. 



Fie 



:?14 a — c. — Monograptus crispus, Lapworth 



i 



Polypary slender, 2 — 3 cm. in length, distal portion broadly incurved, proximal 

 portion strongly recurved, very slender but widening rapidly throughout to 

 a maximum breadth of rather less than 1 mm. Thecce seven to nine in 10 

 mm., of the general type of those of M. lobiferus, but with even more of 

 each theca involved in the conspicuous lobe. Overlap insignificant. 

 Description. — -The polypary when complete has the form of a note of interro- 

 gation, the thecae being first upon the con- 

 vex and then upon the concave side. The 

 very slender, recurved proximal portion 

 is, however, but rarely preserved ; it is, as 

 a rule, composed of the sicula (with a 

 length of about 1 mm.), and two or three 

 extremely slender thecas, of which the 

 earliest arises close to the apex of the 

 sicula. 



The thecae differ somewhat in appear- 

 ance in different portions of the polypary. 

 Of the adnate region of the theca in the 

 proximal portion scarcely anything can be 

 seen, the theca appearing to consist almost 

 entirely of lobe, occupying three-fourths or 

 more of the breadth of the polypary ; dis- 

 tally, however, the adnate region becomes 

 somewhat more conspicuous, and rather 

 more than one-half of the thecal length is 

 involved in the lobe, which is still the most conspicuous feature of the slender 

 polypary, and occupies fully two-thirds of its total breadth. These distal thecce 



#"4 



(Si. 





2? 



• i. Proximal portion, showing sicula. Enlargement 

 of part of PL XLV, fig. 6 c. 



b. Median portion, showing change in character of 



the thee®. Enlargement of part of PI. XLV, 

 fig.6 e . 



c. Distal thecae, showing lobed apertural regions. 



Meigle Quarry, Galashiels ; Gala Beds. Coll. 

 Lapworth . 



