304 Prof. E. W. Claypok — On a New Carboniferous Trilohife. 



Fhillipsia Fortloeki, M. and W. 1865. 

 EuRLiNGTON Group ,, insiffnis, Win. 1863. 



,, tuberculata, M. and W. 1870. 



KixDEEHOOK ,, 1 Doris, Win. 1865. 



,, Rockfordensis, Win. 1865. 



,, "^ Missouriensis^^hvim. 1858. 

 ,, Tentiesseensis, Win. 1869. 



Troetus ellipticus, M. and W. 1865. 



Two other Canadiau species of uncertain horizon complete the list : 



Fhillipsia Bowi, Billings, 1S63. 



„ Vinclobonensis, Hartt, 1868. 



On both sides of the Atlantic therefore, so far as I am aware, the 

 Carboniferous Trilobites without exception belong to the type pos- 

 sessing a pygidium with definite, even outline, like that of the two 

 genera given above. It is true. Meek says, in his description of 

 Fhillipsia Lodiensis (Pal. of Ohio, vol. ii. p. 324) : " The fimbriated 

 character of the p)osterior and lateral margins of the pygidium is 

 very peculiar and hitherto unknown, I believe, in either of the above- 

 mentioned genera" {Phillipsia and GriffitMdes), "though it occurs 

 in one section (^Phaethon) of the allied genus Proetus ; hence, it is 

 possible that our species should be called Proetus (Phaethon) Lodi- 

 ensis, as it would not be very surprising that this genus should be 

 found in this oldest member of the Carboniferous, though hitherto, I 

 believe, only known in the Silurian and Devonian." ^ 



The crenate character of the margin of the pygidium here alluded 

 to must have been exceedingly slight in the typical specimen, as not 

 a trace of it appears in the figure (pi. xviii. fig. 3). Prof. Meek says 

 of this feature, " The segments are continued down upon and across 

 the sloping border, at the edge of which they terminate in little 

 pointed projections so as to present a fimbriated appearance around 

 the posterior and lateral margin. (This latter character is not re- 

 presented in the figure)." 



It is obvious from the terms here employed that the crenation 

 alluded to in no wise resembles the pointed and almost spinous 

 margin of the species described below. I may add that specimens 

 of Phillipsia Lodiensis from the Cuyahoga shale of this county 

 (Summit), only a few miles from the locality of Prof. Meek's type, 

 show no perceptible crenation. 



In regard to the two species of Proetus on the list given above, 

 P. ellipticus and P. auricidatus, a few words may be added. I have 

 not seen specimens of either, but the description of the former by 

 its authors shows that it dilfers very slightly, almost imperceptibly 

 from Phillipsia. They remark in conclusion, " It is very probable 

 that we should call this species Phillipsia elliptica, as it seems to 

 present most of the characters of that genus. Unfortunately, the 



1 Omitted from Miller's Catalogue. 



* Assigned to the Coal-measures in Miller's Catalogue. 



^ In writing this sentence, 1875, Prof. Meek seems to have forgotten his own 

 Proetus ellipticus of 1865, and Prof. Hall's Froetus auricidatvs of 1861, the former 

 from the Kinderhook, and the latter from the Wayerley Sandstone. 



