90 
singular trilobite remains, and it is doubtful whether 
what is said to be the punctured fillet, “nearly 
straight in front of the middle lobe,” be not the com- 
mencement of the articulations of the abdomen. The 
whole fragment looks very much like the head of 
some large Asaph or Ogygia. 
Genus BroneniaTia. Haton. 
Professor Eaton has proposed the name Brongnia- 
tia (Brongniartia?) for a genus of trilobites, which 
we think he has not defined with sufficient accuracy 
to be of ay practical use. The /sofelus gigas of 
Dr. Dekay, which has been for a long time so well 
established, i is here ranked merely as a species under 
the name o B. isotela. The relic which we described 
before the Geological Text Book appeared as the 
Priarthrus Beckit, forms the species B. carcinodea— 
_ and the trilobite which is supposed to be the Asaphus 
platycephalus of Stokes, is the only other species 
mentioned. The A. platycephalus,* we know to be 
identical with the I. gigas, and as the animal remain 
described by Mr. Eaton is entirely different from Dr. 
Dekay’s fine species, we subjoin the account given in 
the “ Text Book.” 4. ; : 
Genus Brongniatia—Fore abdomen always, and 
post abdomen in some cases, longitudinally divided 
into three lobes, by regular series of undulations tra- 
* For a figure and description of the Asaphus Platycephalus, 
a 
by Mr. Stokes, see baci” iy: eiitlic — danse? Se 
cond Series, vol. i. 
¢ a 
a Oe 
. 
Baek ne é oT ee a ea 7) 
