884 J. E. MARR ON LIFE-ZONES OF THE 



Appendix. On some Species of Phacops. 



1. Phacops (Chasmops) macroura, Sjogren. 



I would add the following notes to the description given of this 

 Trilobite by Salter, Mon. Brit. Tril. pp. 37, 38. 



The tubercles mentioned on p. 38 are not arranged at random, 

 but in roughly linear series, the lines running from before back- 

 wards ; they are more largely developed behind than in front, and 

 more on the glabella than on the cheeks, being especially marked 

 on the " cat's-ear " lobes. The double row of puncta seems to be 

 characteristic of the species, as I have seen it in at least four speci- 

 mens in the Woodwardian and Geological-Survey collections. 



Body-rings of the axis nearly uniform in breadth and width, being 

 convex. Pleurae more than twice as wide as the axis, slightly curved 

 downwards at the outer extremity, and ending obtusely. Pleural 

 grooves deep, straight throughout, oblique, running parallel to the 

 sides of the pleurae at the outer extremity. 



The body much resembles that of P. truncato-caudatxis, Portlock, 

 from which it differs in the uniformity of the body-rings of the axis, 

 the total want of tuber culation, and the much greater curve of the 

 furrows bounding the pleurae. 



Formation, Coniston Limestone. 



Localities. Coniston ; Applethwaite Common (a beautiful speci- 

 men, with the head and seven body-rings preserved, was found there 

 by E. Marr, Esq.) ; Long Sleddale ; Style End (in beds below the 

 felspathic rocks). 



2. Phacops (Odontochile) mucronattjs, Brongn., var. 



I have found numerous specimens of a Phacops in the Lake- 

 district corresponding to the description given by Salter (Mon. Brit. 

 Tril. p. 46) of a Trilobite from the slates of Pen-y-rhiw, near Bala. 

 No body-segments have yet been found, but numerous heads and 

 tails. The head is strongly tuberculated ; the cheek possesses a 

 spine at the outer corner. The tails are like that figured by Salter, 

 and probably possessed a long spine, of which the cast is preserved 

 in one specimen in my collection, whilst other specimens show indi- 

 cations of its having existed. 



The species much resembles P. obtusicaudatus, Salt., as regards 

 the head; but the furrows of the glabella are much straighter and 

 shallower, whilst the lobes are nearly equal in width throughout, 

 and all of nearly the same size. The species will probably have to 

 be ultimately separated from P. mucronatus and placed under Salter's 

 title, appendicidatus. 



Formation. Ashgill Shales. 



Localities. Ashgill ; Skelgill, Nanny Lane, and Applethwaite 

 Common, Troutbeck. 



3. Phacops (P. proper), sp. 



A specimen from a bed in the Graptolitic mudstones of Skelgill 



