46 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO3

ARAPAHOIA ALBERTENSIS, new

species

Plate 7, Figures 27-31

This is a very

abundant

species

and

is

normal

for the genus. Its

outstanding characteristicis the

enormous

posterolateral limbs,

which

havepushed the rear facial suture

forward

nearlyto the front

margin

of theglabella. In exfoliated specimenstheglabella is clearly

marked

by four pairs of glabellar furrows.

The

shallow occipital

furrow marks

off a triangularneck ring extending into a longoccipital spine.

A

tubercle near its base

seems

to be a

median

eye. Anterior facial suture diverges very little

and

evidently is intermarginal nearly to the center.

The

libragene assigned to the species is short

and

stout, to^fit with the contour»f the facialsuture.

The pygidium

assigned to the species is also short

and

has a well-defined border.

Sullivan formation; (loc. 64h) East Lyell Glacier, 48 miles north- west of

Lake

Louise, Alberta.

Ilolotypc.

— ^U.S.N.M. No.

108705a; paratypes, Nos. 108705b,e.

ARAPAHOIA PROLIXA, new

species

Plate 7, Figures 20-26

This large species is represented by a

number

of specimens. In length it resembles A. clongata.

On

^exfoliated specimens theglabella is clearly defined

and shows

faint traces of glabellar furrows.

The

outer test hasa keel.

At

the anterior end of the eye the fixigenesare narrow,

measuring

a little

more

than the width of the dorsal furrow.

Anterior to the eyes the suture diverges, but less thanin A. elongata.

In cross section the species has

low

convexity, attained

by

an even curvature. Longitudinally it has greater convexity but this is also attained witheven curvature. Concentric linesappear just behindthe midpoint ofthecranidium

and

possibly surround aneye.

On

theother hand, the

brim

is characterized by vertical anastomosing lines,

which

are stronger

on

exfoliated specimens. Unfortunately

no examples

are complete but a rather

wide

libragene seems to represent the species.

The pygidium

assigned to the species is convex, with a fairly well- defined border. It has definite pleural furrows

and

grooves.

Sullivan formation; (loc. 64h) East Lyell Glacier,

48

^milesnorth- westof

Lake

Louise, Alberta.

Holotype.

— ^{U.S.N.M. No.}

^108704a: i)aratypes. Nos. io8704b-d.

ARAPAHOIA WALCOTTAE,

new species

Plate 7, Figures 12-14

This is a short

form

similar to A. albertensis. In cranidia that retain the test the outline of the glabella is indicated by a shallow

so. ₅

UPPER CAMBRIAN

TRILOBITES RESSER

47

dorsal furrow. Exfoliated specimens have the glabella

much more

sharply defined,

and

glabellar furrows are represented

by

pits.

The

eyes are slightly farther back than in

A.

albcrtensis.

The

suture diverges in front of the eye

and forms

large posterolateral limbs behind the eye.

The

middle portion of the

brim

projects somewhat.

In cross section thecranidium has considerable elevation, attained

by

sharp curvature of the top of the glabella

from which

the postero- lateral limbs

bend downward

with approximately the

same

slope.

Longitudinally the species is not greatly curved.

Sullivan formation; (loc. 6^e) East Lyell Glacier, 48 miles north- westof

Lake

Louise, Alberta.

Holotype.

—

LT.S.N.M. No. 108702a; paratype, No. 108702b.

PLETHOMETOPUS

Ulrich, 1930

PLETHOMETOPUS ALBERTENSIS, new

species

Plate 12, Figure 13

A

singlecranidium, typicalof thegenus inall respectsissufficiently well preserved to warrant naming.

The

simple large glabella, indi- cated

by

^a faint dorsal furrow, is about three-fourths the length of the head,

and

tapers slightly to a

rounded

anterior margin.

A

strong occipital

furrow

separates a neck ring that extends into a short blunt spine. Fixigenes narrow, measuring at the eyes about a fifth the glabellar width.

The

posterolateral limbs are small

and

possiblyshort.

Eyes

small, situated about the midpoint of the glabella. In cross section the cranidium is rather evenly curved, while longitudinally the curvature is

much

greater, particularly in the anterior half.

As

a result the simple brim is

convex

in both directions.

A

faint broad anterior

furrow

is visible in the anteriorangles.

Lyell formation; (loc. 20j) Tilted

Mountain

Brook, 97 miles east of

Lake

Louise, Alberta.

Holotype— \JSMM.

^No. 108755.

KINGSTONIA

Walcott, 1924

KINGSTONIA ELECTRA, new

species

Plate 7, Figures 33-36

This species is represented

by

a

number

of cranidia, but thus far no

pygidium which

can be assigned to the species has been located.

On

the outer surface the cranidium

shows few

features. It is highly arched in both directions,

becoming

almost hemispherical. Indeed its

outline departs slightly

from

a semicircle only

by

a flattening of the curvature at about the midpoint of the cranidial length.

A narrow

brim ispresent. Exfoliated specimens sliowa clearly definedglabella,

48

SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL. 103 which extends to the anterior

margin

of the cranidium.

A

narrow- occipital ring is indicated.

Weeks

formation; (Iocs. 3oh, i) 5 miles south of

Alarjum

Pass.

Mouse

Range, Utah.

Ilolotype.

— ^U.S.N.M.

No. 108706a; paratypes, No. 108707.

KINGSTONIA MUCRO,

new species

Plate 8, Figures 1-8

This rather large species is represented hy

some

20 specimens, it is characterized by

enormous

posterolateral limbs,

which

give the cranidium great v^idth

and

cause ^it to depart

from

the

more

nearly semicircular outline of

most

species.

The

glabellais faintly indicated,

more

particularly in the rear

where

shallow furrows extend forward for

some

distance.

There

is a

narrow

rim of the usual type.

The

eyes are of

normal

^size

and

situated

somewhat

in front of the mid- point. Incross section the headis strongly arched.

The

posterolateral limbs continue the

downward

slope, with increasing curvature near their distal ends. Longitudinally the cranidium is highly arched.

The

associated pygidium,

when

viewed

from

the dorsal surface, has a

rounded

triangularshape. In profileitis very convex.

At

the anterior angles the sides stand^vertical, but posteriorly the curvature increases until at the rear of the axis the

pygidium

is folded under.

The

axis

is faintly outlined

and

in exfoliated specimens

shows

six rings.

Pleural grooves are visible.

Sherbrooke limestone; (loc. 58f) ridge west of

Mount

Bosworth, British Columbia.

Holotype.

— ^U.S.N.M.

No. 108709a; paratypes, Nos. loS/oga-d.

KINGSTONIA BOSWORTHENSIS,

new species Plate 8, Figures 9-13

This species has

normal

size and shape.

The

cranidium is quite globular withonly short posterolateral limbs,

and narrow brim around

the front. In cross section the cranidium stands very high with its

greatest curvature

toward

therear. Longitudinally^it is curved rather evenly throughout, with a slight flattening in the front fourth.

The

associated

pygidium

is short

and

very convex.

Sherbrooke limestone; (loc. 57p) ^ridge west of

Mount

Bosworth, British Columbia.

Holotype.

— ^U.S.N.M.

^{No. 108710a; paratypes, Nos. 108710b, c.}

NO. 5

UPPER CAMBRIAN TRILOBITES—

RESSER

49 KINGSTONIA ROBSONENSIS, new

species

Plate 8, Figures 14, 15

A

single cranidium, fortunately rather well preserved,

was

found in the collection,

showing

that the Sullivan formation should berecog- nized in the

Robson

District. This cranidium is of average size

and

shape.

The

glabella is defined by a complete dorsal furrow,

which shows

as a darker line through the test but is not expressed as a furrow.

A narrow

striated

brim

is present

and

the posterolateral limbs are wide

and

bluntly

rounded

at the ends.

Sullivan formation; (loc. 6ir)

Moose

River, lo miles northeast of

Robson

Peak, BritishColumbia.

Holotype.—U.S.'NM. No.

108711.

KINGSTONIA SULLIVANENSIS, new

species

Plate 8, Figures 16-19

This globular species with rather large posterolateral limbs has a faintly defined glabella.

A

^distinctly thickened

and

striated rim char- acterizes the holotype.

The

posterolateral limbs are

rounded

off abruptly.

Sullivan formation; (loc.

64m)

Sullivan Peak, 48 ^miles northwest of

Lake

Louise, Alberta.

Holotype.

— ^U.S.N.M.

No. 108712a;paratypes, No. 108712b.

KINGSTONIA PROMISSA, new

species Plate 8, Figures 20-23

Numerous

^cranidia

and

a

few

pygidia represent this species, which

is slightly smaller than average. It is a short

form

with relatively wide fixigenes

and

large posterolateral limbs.

The

glabella isoutlined only in the rear. In cross section the cranidium is very convex; the convexity being attained by the steeply inclined posterolateral limbs

and

a very sharp bending at the top of the ^glabella. Longitudinally the convexity is that of a quarter sphere.

The pygidium

is very plump, swelling greatly

toward

the rim.

Sullivan formation; (Iocs. 64c, j) Glacier

Lake Canyon

Valley,

48

milesnorthwestof

Lake

Louise, Alberta.

Holotype.

— ^U.S.N.M. No.

^{108713a;paratype.}

No.

108713b.