Mr. C. Lapworth on new British Grrctpfolites. 155 



7. Monograptus crassus, Lapw., sp. nov. 

 (PI. IV. fig. 8 h.) 



Monograptus Haiti, Barr., Camithers, Geological Magazine, vol. v. ; 

 Lapworth, ibid. vol. iii. (1876), pi. xiii. tigs. 1 «-l d, &c. 



Poljpaiy straight, one tenth to one eighth of an inch in 

 diameter. Hydrothecas eighteen to twenty to the inch, short 

 and stout slightly overlapping tubes, half as long again as 

 broad, furnished with distinct horizontal spines. 



I have hitherto followed Mr. Carruthers in his reference of 

 this form to Monograptus Halli, Barr. ; but there can be no 

 question of its distinctness from Barrande's typical form, in 

 which the hydrotheca3 are very differently formed (comp. 

 fig. 9 a.) 



Horizon and Locality. Common in the highest beds of the 

 Birkhill shales everywhere in South Scotland. 



8. Monograptus riccartonensis, Lapw. 

 (PL IV. fig. 8 c.) 



Monograptus riccartonensis, Lapworth, Geological Magazine, vol. for 

 1870, pi. xiii. tigs. 2 a-2 e. 



Polypary never exceeding one twelfth of an inch in trans- 

 verse diameter, proximal portion slightly recurved. Hydro- 

 thecae twenty-four to twenty-eight to the inch, free, with 

 direct walls, everted aperture, ornamented with a long and 

 oblique spine. 



A narrow species, with distant free hydrotheeaj. Salter's 

 species M. Flemingii was probably founded in part upon this 

 form, partly upon the following species. They are both pre- 

 sent in Salter's original locality of Kirkcudbright, the present 

 form " in great plenty," while the next species is compara- 

 tively rare. 



Horizon and Locality. Very numerous in the Wenlock 

 strata of Eiccarton and Kirkcudbright, rare in the Coniston 

 Flags of Westmoreland, and in the Llandovery strata of Tieve- 

 shilly, county Down, Ireland. 



9. Monograptus Flemingii, Salter. 



Monograptus Flemingii, Salter, Quart. Journ. Geol. Soc. vol. viii. 

 pi. xxi. figs. 5, 6, 7 ; Lapworth, Geological Magazine, 1876, pi. xx. 

 fig. 8, a-d. 



Polypary straight, one tenth to one eighth of an inch in 

 diameter. Hydrothecte twenty to thirty-six to the inch, over- 

 lapping each other for more than half their length, from three 

 to four times as long as wide, with slightly curved separating 

 walls, and greatly expanded apertural margin, which in com- 



