64 
BULLETIN OF THE LABORATORIES 
Phillipsla, triniicleata, n- sp. 
A considerable number of specimens have been collected which 
were at first supposed to be P. sangamo 7 ieiisis, but are evidently quite 
distinct from any described species. It is not absolutely certain that 
the cheek spine belongs to the same species as the glabella and pigidia 
with which it was associated, yet the circumstances render it highly 
probable. 
The glabella presents the most distinctive features. It is considera- 
bly longer than wide and quite convex, the greatest height being poste- 
rior to the middle. An^-erior depressed margin rather narrow in front, 
expanded laterally; sides nearly straight' or somewhat concave near 
the eyes ; postero-lateral lobes very sharply defined, conical, oblique, 
with a second smaller pair in front of them, and a very faintly out- 
lined second pair still farther forward ; between the postero-lateral 
lobes a sharply defined, prominent, median elevation, almost as large 
as the others; cervical segment convex, high, often with a single me- 
dian tubercle. The surface of the glabella is minutely ornamented 
and on either side in front of the eyes is an oval pit which has been 
thought by some to represent the insertion of the antenna or organ of 
sense. 
The eyes are large and supported by a prominent palpebraral 
lobe. A single movable cheek has been found. The margin is ob- 
liquely inclined, forming a prominent angle at its union with the face; 
middle of cheek depressed and marked with an impressed line ; cheek 
produced into a spine as long as the whole remainder of the cheek ; 
length of cheek, .77 (the spine, .35); length of eye, .11. Pigidia are 
not rare and are very convex, the median lobe especially being con- 
vex from side to side and particularly prominent posteriorly. The 
median lobe occupies one-third or less the wddth of the pigidium prox- 
imally and tapers gradually, forming a portion of a regular truncate 
cone ; on either side an impressed line marking off an accessory por- 
tion; axial segments 17-19; lateral lobes convex; plurae flattened 
slightly above, separated by very deep sutures; margin broad, longi- 
tudinally striate, abruptly deflexed ; ribs 9-12. Length of pigidiuiTi, 
.35 ; width, .45, length of axial lobe, . 27. Another individual, length, 
.48, width, .56, axial lobe, width, .20, length, 40. The pigidium is 
generally, if not always ornamented by minute pistules on the summits 
of the segments which are borne on the top of a slightly elevated, flat- 
tened ridge forming the axis of the annuli. 
