212 F. R. Cowper Reed—Fossils from Dufton Shales. 
Pleurotomaria (?) sp. Siphonotreta scotica, Dav. (?). 
Trochoneme sp. Orthis unguis, Sow.* 
Tentaculites sp. O. testudinaria, Dalm.* 
Conularia aff. plicata, Slater. O. Actonie, Sow. 
Ctenodonta (?) sp. O. duftonensis, sp. nov. 
Pterinea (?) sp. O. melmerbiensis, sp. Nov. 
O. turgida, McCoy (?). 
Bryozoa. 
ras 3 , . (Scenidium ? vivocalis, Sp. , 
Crisinella Wimani, sp. nov. Gea oe ts, Sp. NOV 
Monstnypa\t) sp Leptena rhomboidalis (Wilck.). 
BRACHIOPODA. 
INCERT SEDIS. 
Lingula tenuigranulata, McCoy.* Pasceolus sp 
Lingula sp. 
Orbiculoidea perrugata, McCoy. CRINOIDEA. 
O. oblongata, Portl.* Stem joints (round and pentagonal). 
Acrotreta Nicholsoni, Dav. (?). 
The species marked thus * are most abundant. 
TRILOBITA. 
TrinuctEus NicHonsoni, sp. nov. Pl. XVI, Figs. 1-9. 
Head-shield rather more than a semicircle, widest across middle, 
somewhat contracted at base; posterior margin inclined to lateral 
margin on each side at 75°-80°; fringe sloping downwards but not 
steeply inclined, slightly produced backwards at genal angles which 
are furnished with long spines. Glabella pyriform, much elevated 
and swollen, most so anteriorly, gradually decreasing in width and 
height posteriorly to occipital ring without forming neck; front end 
projects slightly beyond cheeks to fringe or overhangs the inner row 
of pits; small median tubercle present on surface of glabella, and on 
each side near its base are two pairs of small deep pits in axial 
furrows, the posterior pair in occipital furrow. Occipital ring narrow, 
nearly as elevated as glabella, separated off by shallow furrow, and 
furnished posteriorly with a short stout spine directed backwards and 
upwards at an angle to the general plane of head-shield and about 
one-third the length of the glabella. Cheeks forming spherical 
triangles, longer than wide, less swollen and elevated than glabella, 
highest along axial furrows, with posterior outer angle rounded, and 
minute granulation over whole surface. Fringe inclined, sloping 
downwards and widening to genal angles which are provided with 
long tapering genal spines curving first slightly inwards and then 
outwards. In anterior part of fringe are four rows of equal-sized 
pits arranged regularly in concentric and radial rows; the pits in 
outermost row are sometimes rather smaller. On the lower surface of 
the fringe the two outermost concentric rows are separated from the 
inner ones by a strong concentric ridge continued back to the genal 
angles and longitudinally along the spines. In front of and at the 
side of the cheeks the fringe widens slightly, and inside the four 
regular rows are introduced one or two shorter concentric rows of 
smaller pits with less distinct radial arrangement, so that 56-6 rows 
with a few smaller irregularly developed pits can be detected at the 
posterior outer angles of cheeks rounding them off. In some specimens 
the pits near the genal angles tend to be alternate. The true genal 
angle (i.e. the base of the spines where the pitted fringe ends) is level 
