458 



BRITISH GEAPT5LITES. 



Horizon and Localities. — Gala Beds. 

 S. Scotland: Blythe Water, Lauder. 

 Associates.— "-Unknown. 



Collection. — Geological Survey of Scotland. 



Monograptus capillaceus, Tullberg. Plate XLVI, figs. 4 a—d. 



1883. Monograptus capillacevs, Tullberg, Staines Graph, ii, p. 2-1, pi. ii, figs. 28, 29. 



Polypary several cm. in length, conspicuously flexed, generally incurved distally 

 and recurved proximally, widening persistently from a very slender proximal 

 portion to a maximum breadth of about 1 mm. Thecse eight to ten in 10 

 nun., of the general type of those of M. lobiferus, but with only a small 

 fraction of the total thecal length involved in the lobe, which only occupies 

 one-fifth of the total breadth of the polypary. Overlap insignificant. 

 Description. — The polypary is usually from G — 8 cm. in length and occasionally 

 even more. British examples are frequently rather more arcuate distally than is 



the case with the Swedish specimens, some indi- 

 viduals making a more or less complete S-bend. 

 The polypary widens persistently throughout its 

 length, fairly rapidly in the extreme proximal 

 portion but to so slight a degree distally that frag- 

 ments of the distal portion seem to have an approxi- 

 mately uniform breadth. 



The sicula is small, not exceeding 1 mm. in 

 length, and th. 1 arises from it shortly above its 

 aperture, so that the apertural region of the sicula 

 alone forms the termination of the polypary, which 

 is very slender, not exceeding "3 mm. in breadth. 



The proximal thecse are longer, more slender, 

 and more distant than the distal ones, measuring 



Fios. 316 a—c. — Monograptus capilla- 

 ceus, Tullberg. 





i 





<f 



a. Proximal portion, showing sicula. 



Enlargement of specimen on same 

 slab as PI XLVI, tig. 4d. 



b. Distal thecse. Enlargement of part only eight in 10 mm. lhe proportion of the aper- 



of specimen on same slab as Fig. , . „ 1,1 • 1 1 ■ . 1 • i , • 



3i6a. tural region of each theca involved in the isolation 



c. Distal thecse, showing lobed apertural n . 1 ■ 11 ,1 ,1 



regions. Milk Water at Milk and retroversion is, m this species, so smalt that the 



bridge, three miles S. of Lockerbie, , , • 1 r 1 ,\ . r,. ^.,, j.i, , ,,,,,,,,,,1 1;,, , ,,u - 



S.Scotland. Geological Survey of lobes project but slightly from the general line ot 

 Scotland. ^ ne polypary ; the ventral walls form an almost 



traight line, broken only by the lobes ; the upper walls are very short. 



Affinities. — Monog. capillaceus approaches most closely to M. retrofiexus in 

 its general form, but in this latter species the polypary is much more slender, and 

 does not widen throughout like M. capillaceus, while the lobe is more tightly 

 coiled. 



