i34 Lapworth — Graptolites of Co. Down. 



regularly disposed in two opposite series, and sometimes irregularly scattered 

 along the extent of the outer margin of the polypary. 



These forms are all certainly allied to Glossograptus, but our present 

 evidences are insufficient to justify their removal to that genus. Locality — 

 Carnalea. 



47. Sp. 15. Diplograptus Whitfieldi. Hall. PI. 6, fig. 21. 



The interesting examples furnished with lateral reproductive appendages, 

 figured by Hall in his Graptolites of the Quebec group, Plate B, and assigned 

 by him to the present species, are clearly distinct. It is most probable that 

 they belong to a form of Lasiograptus (?) resembling Lasiograptus 

 bimucronatus, Nich. Locality — Carnalea. 



48. Sp, 16. DiplograpUis ( Lasiogtaptusl ) mucronatus. Hall. PI. 6, fig. 22. 

 In this series the apertural fibres occasionally anastomose; and examples 



with lateral reproductive appendages are not infrequent in the Moffat Series in 

 Scotland. In Ireland the species is as yet unknown. 



49. Sp. 17. Diplograptus ( Hallograptus ) bimucronatus. Nich. PI. 6, fig. 23. 



It is in this species that the lateral reproductive processes are most 

 frequently met with in British Rocks. Few examples of this form occur which 

 appear wholly destitute of them, or of the lateral fibres which support them. 

 Mr. W. Carruthers has suggested that this form, and the very similar 

 Diplograptus mucronatus should be erected into a new genus under the title of 

 Hallograptus, in honour of the eminent palaeontologist, who was the first to 

 figure these forms and to suggest the possible function of their remarkable 

 appendages. 



Genus VI. Glossograptus. Emmons. 



50. Sp. I. Glossograptus Hincksii. Hopk. PI. 6, fig. 24. 



The lateral appendages in this species and genus differ from those in 

 Hallograptus, in being rigid blind spurs comparable with those at the proximal 

 extremity of Climacograptus bicornis (Hall). In all the supposed species of this 

 genus, the apertural spines are also remarkably stout and rigid, but they never 

 anastomose as in the older and very closely allied genus Retiograptus of Hall. 

 (Grapt. Quebec Group, Plate 16, figs. 6 to 8). Glossograptus ciliatus, Emmons 

 (American Geol.^vol. 1, plate 1, fig 25); Glossograptus setaceus, Ibid. Fig. 



