58 
BULLETIN OF THE LABORATORIES 
united segments, axis rather more than one-third the entire^proximal 
width, tapering gradually to its blunt prominent distal extremity, which 
is near the margin, strongly elevated and ornamented by a series of 
tubercles on each of the segments, which are circular in section and 
separated by deep, narrow grooves; pleural portions suddenly and 
strongly deflected at a short distance from the axial lobe, but becom- 
ing less oblique to form the narrow margins which are not otherwise 
defined, the nine or ten pleural ribs are elevated and keeled, the keel 
bearing from two to five small tubercles and extending out upon the 
free margin as a strong rib, terminating in a tooth or tubercle on the 
free margin ; length of pygidium four-fifths or more of the width. 
Length of pygidium, 8 mm., width, lo mm. Length of head-shield, 
7 mm., length of glabella, 4.4 mm. 
Several heads and pygidia were collected in conglomerate II at 
Granville and Newark. 
PHAETHONIDES SPINOSUS, sp. n. 
(Plate I, Figs. 4-5.) 
Glabella two-thirds as long as head including the neck-segment, 
narrow, not much expanded posteriorly, form much as in P. occiden- 
talis, but with smaller postero-lateral lobes and no indication of an an- 
terior pair of grooves. Anterior margin of head narrow, separated 
from the median lobe of glabella by a very shallow concavity which 
becomes convex as it nears the glabella. Surface profusely set with 
high tubercles, those upon the glabella forming about eight rows, lat- 
eral lobes with three small spines. 
Pygidium of large size for the genus, very convex and much 
arched, composed of fourteen coalesced segments, axial lobe elevated, 
its segments moderately convex, separated by comparatively shallow 
and not very narrow grooves, and ornamented by five sharp almost 
spinous tubercles, of which the central one is largest and separated 
from the lateral ones by a greater interval than separates the latter; 
pleural surfaces convex, suddenly depressed near the middle of their 
width nearly perpendicularly to fhe shallow groove separating the very 
narrow margin; eight or nine pleural ribs carinate, with from one to 
four spinous tubercles, ribs nearly disappearing in the marginal groove 
but springing into an oblique acute spine on the raised margin. The 
ribs of the pleura bifurcate near the margin by the division of that por- 
