 * 
16 “a 
and wee monography of American trilobites. The 
present specimen is undoubtedly American, though 
Mr. Acer expressed some doubt as to its precise 
locality. He supposed it to be from Trenton Falls, 
in the State of New York. I have the honour to be 
respectfully your friend, 
RicHarp aneniin) 
s e P. Harlani is in flinty siliceous slate, it 
does n t probably occur at Trenton Falls, where the 
rocks are mostly formed of carbonate of lime. Our 
species resembles very much the P. Tessini of Brong- 
niart, a representation of which he gives from Prof. 
Wahlenberg, on plate 4, fig. 1, which fossil’ is the 
old Entomolithus paradoxus of Linnzus,’ and has 
been found only in Westrogothia, at ver 
septa ‘dans vee. coneuee d’ampelite alumineux. si 
Pe ERER, See nccdanae: * Green. Cast No. 40. 
Clypeo — ? Corpore depresso; 3 costis latis, convexis, 
tuberculis magnis ; cauda rotunda a 
The large fragment, by means of which this species 
has been identified, is in a fine state of preservation. - 
Thirteen costal arches and fourteen joints of the 
middle lobe, with two or three faintly marked ar- 
ticulations near its extremity, can be very satisfac- 
* From the Greek for “* wart ribbed.” 
“In Silliman’s Journal, where this species’ was first published, 
the specific name was by mistake printed Myrmecoid 
however, corrected in the errata of that work. 
