106 lite Ahienoaii Geologist. February, i893 
AMPYX AMERICANUS AOudes & Satfoid, 1SH!». 
JXagiiosis. — (TOiU'itil outline hrondly ovul; gliilxdla somewhat 
claviforrn. slightly convex, luinowino- heh'md the middle and 
widening out slightly at its junction with tlic occipital ring: it is 
marked on ctich side by one or more obliciue furrows: projecting 
spine broken off in the specimen before us. The cheeks are 
broad and rounded towards the margins: genal spines broken ofT: 
facial sutures not o))served. The thorax has six horizontal seg- 
ments: the axis is broad niiteriorly :ind gradually diminishes 
posteriorly: it is well defined l)v the dorsal furrows and lateral 
nodes along its sides. 'I'he pleune are horizontal and deeply 
grooved, terminating in obtusely pointed ends like those of Anipi/a- 
nudvs ^lurch. The pygidiuni is triangular in form: the axis is 
prominent and gently ta[)ering to an ()l)tuse point on the posterior 
border: it is marked by 11] or more rings with a central row of 
nodes: the sides have only one pair of side ril)s which are deeply 
grooved outwards, cutting oH' the posterior j)art of the tail. 
Geolofticiil jiosifioii. — Trenton ^Toup near lUilTs (bi]). on the road to 
Rnsselville, Tennessee. Cabinet of J. ]M. Safford. 
Activities. — We have compared tlie Tennessee speeies with the 42 
known species of the genus Anipj'v, and find that it differs in detail 
from all of them. The American species is of the type Ampij.r nndus 
Murch and A. cosfatns Boeck. There is a pygidium figui-ed by Billings 
in Palajozoic Foss, Canada, vol. i. j). 2!)"). fig. 285, as Ampi/.r lnviusciilus 
from Table Head X. F.. whicli appioaclies the Tennessee species, but 
it lacks the nodes. 
L<>)i(jlfi<>}it(s. 
ViG. .". Aiiij/i/.r Inlli Bii,i.. 
AMPYX HALLI Killings, IStil. 
Diaynosiit. — Head somewhat triangular or semi-oval: glabella 
elongate-oval, termimiting in front with an acute spine and 
truncated behind by the neck furrow, narrowly convex and rather 
sharply carinated along the nnnlian line: glabella furrows repre- 
sented by two obscure indtMita lions on each side, the posterior at 
a little less than one line from the neck segment, and the anterior 
about two lines: the latter consists of deep pits situated in the 
