G. F. Matthew—Paradoxides Kjerulfi. 391 
The position of No. 4, or the beds carrying P. dlandicus, was 
said to be doubtful, as not determined by observed sections of 
the Cambrian beds; it is however the horizon assigned by Mr. 
A. Sjégren the describer of the species. 
Having observed the stratigraphical position of the Acadian 
representative of this species (P. lamellatus Hartt) to be below 
the beds which carry the Acadian species allied to P. Zessina 
the writer ventured to inquire of Professor Lindstrom of Stock- 
holm what the position of P. dlandicus was, and by a letter 
lately received from that gentleman he learned that “in 1875 
Professors Nathorst and Dames found the zone of P. dlandicus 
to be older than that of P. Tessini.” 
The importance of this fact is the greater from the many 
points of affinity between this species (P. dlandicus) and P. 
Ajerulfi. Mr. Ford in his valuable article above referred to, 
speaks of ‘‘a number of strong points of resemblance” between 
these species, but does not specify the point wherein the rela- 
tionship consists, but some of the more salient ones will 
appear from what follows. 
If it could be shown that the lower part of the Para- 
doxides beds in America is characterized by a group of 
species which differ from the typical Paradoxides found higher 
up, an advance would be made in distinguishing the sev- 
eral parts of the Cambrian system on this side of the Atlantic. 
That there is such a group at the base of the Paradoxides zone 
in Kurope and America is now I think sufficiently clear; and 
some of the points of structure which mark it are the follow- 
ing: The lest is granulated, the pleural yrooves are short and 
strongly marked, the glabella and rachis are prominent, the fixed 
cheeks are narrow, the eyelobes are shortened and drawn in at the 
base, the genal spines are short (and channelled on the upper side?).* 
In P. Kjerulfi the pygidium is not known; in P. dlandicus 
the pygidium has four points; in P. damellatus the pygidium 
has two points. 
In the second and third species the pygidium is that of Para- 
doxides, not of Olenellus, and it is a matter still to be deter- 
mined whether the first named species is a true Olenellus in all 
respects, and especially as regards the pygidium. 
In Paradoxides Acadicus we have another primitive type, but 
not of the same section in Paradoxides as those above named. 
The recovery of the parts show that it possesses the long sig- 
moid pleural furrow of the more typical forms of the genus 
and not the comma-shaped (almost pear-shaped) furrow of the 
three species above named. It has not yet been found so low 
down in the Acadian (Cambrian) measures as some other 
* They are channeled in P. Kjerulfi and P. lamelilatus. 
