Lapworth— Graptolites of Co. Down. 135 



20; Diplograptus ciliatus, Ibid. Fig. 19; Diplograptus spinulosus, Hall. 

 Diplograptus fimbriatus, Hopk. (Geol. Mag., 1872. PI. 12, fig. 8.) 

 Diplograptus pinguis, Ibid. Fig. 7 ; all belong to this genus and will pro- 

 bably prove to have been founded o» either one or two distinct species : the 

 aspect of the polypary varying to an extraordinary degree according to the 

 direction in which the compression has been effected. Localities- -Coalpit Bay 

 and Ballygrot. 



Genus VII. Lasiograptus. Lapworth 



51. Sp. I. Lasiograptus Harknessi. Nich. PI. 6, fig. 26. 



An examination of Nicholson's type specimen of his Diplograptus Hark- 

 nessi has convinced me that it is identical with my Lasiograptus costatus, which 

 must consequently be suppressed. This species has a great range in the Moffat 

 Series, passing upwards from its very lowest beds into the middle of the Hart- 

 fell Shales. Occasionally a specimen is detected in which the ventral spines are 

 rudimentary and do not anastomose. Locality — Carnalea. 



52. Sp. 2. Lasiograptus margaritatus Lapw. PI. 6, fig. 25. 



Polypary diprionidian, about one inch in length and about one-eighth of 

 an inch in diameter, inclusive of the marginal net-work. Virgula ca- 

 pillary, just visible beyond the distal margin Hydrothecse. 25 to 30 to 

 the inch, free, triangular in form, with long-pointed denticles which 

 are developed horizontally outwards as distinct filaments to a distance 

 equal to the width of the central portion of the polypary, where they 

 are split up into several subordinate threads. These are united to those 

 similarly derived from the hydrothecse immediately above and below, 

 and thus originate a continuous series of marginal meshes completely 

 surrounding the polypary. 



In this species the hydrothecse are of the type of those of Diplograptus 

 mucronalus (Hall), and the general aspect of the polypary is essentially similar 

 to that of Diplograptus limucronatus (Nich.). In Lasiograptus Harknessi the 

 thecee resemple those of Climacograptus . Locality — Unknown in Ireland. 



Genus VIII. Clathrograptus. Lapworth. 



53- Sp. I. Clathrograptus cuneiformis. Lapw. PI. 6, fig. 27. 



The figure shows merely the skeleton framework of the polypary. In well 



