52 
BULLETIN OF THE LABORATORIES 
Phillipsia. 
General form oval. 
Head never over one-third the 
length and shorter than pygidium. 
Head surrounded by raised bor- 
der. 
Glabella with parallel sides. 
Basal lobes separated by a dis- 
tinct furrow from rest of glabella. 
Glabella with two or three fur- 
rows. 
Free cheeks produced into 
spines. 
Cervical suture deep, cervical 
segment high. 
Eye large, facetted. 
Thoracic segments nine (or ten.) 
Pygidium with a rounded bor- 
der which is usually narrow. 
Number of segments large (from 
10-18.) 
Proetus. 
Do. 
Head shorter than one-third and 
shorter than pygidium. 
Do. 
Do. 
Do. but smaller and 
more transverse. 
Glabella with three more or less 
distinct furrows. 
Free cheeks triangular less, fre- 
quently with spines. 
Do. 
Do. 
Thoracic segments eight to ten. 
Border of pygidium rather broad 
and flat. 
Number of segments less (4-13). 
PHILLIPSIA SERRATICAUDATA, sp. n. 
(Plate I, Fig. 8, a — d.) # 
Glabella a little longer than wide, apparently about one-third as 
wide as entire shield, moderately elevated, surface rather depressed, 
narrower anteriorly, marked by three distinct lateral sulci with some 
indications of a fourth ; postero-lateral (basal) lobes rather small, very 
oblique ; produced back of the median lobe ; the second and third fur- 
rows short, near together but separated by a wider interval from the 
first and less oblique. The elevated median lobe is separated by the 
very narrow anterior border by a narrow deep sulcus ; neck segment 
very broad. Only a part of the movable cheek has been seen and it 
cannot be determined whether it is mucronate or not. 
Outline of pygidium parabolic, length about two-thirds the width; 
median lobe rather convex, composed of about twelve segments which 
are separated by rather deep rounded grooves ; lateral lobes moderate- 
