‘THE FAUNA OF THE ST. JOHN GROUP. 91 
the cemetery of countless myriads of adult forms, it is not surprising that the wealth of 
fragmentary tests is bewildering ; and when to this is added the variety of appearance given 
to the test of each species by the forces which produced cleavage in the slates, the profusion 
of shapes is exceedingly perplexing, and embarrasses the observer in his attempt to reduce 
this chaos to order. 
Owing to the looseness with which they are organized, as compared to the other trilo- 
bites, and the number of fragments required to complete the skeleton, the Paradoxides are 
not the least puzzling. In only three instances has the writer met with a complete trilobite, 
and none of these are of the genus now under consideration. Therefore the description of 
the species will be confined to the part of the test enclosed within the facial sutures. 
Inter-relationship of the forms. 
One feature in the aspect of the Acadian species of Paradoxides, thus far discovered, 
which immediately arrests the attention is the invariable presence of long eyelobes, set far 
back on the head. In all the species these lobes extend at least as far back as the occipital 
furrow, and generally to the occipital ring, and in a few cases seem to be on a line with 
the back of the ring. In this respect the St. John Paradoxides have a facies differing from 
any others on this continent with which the writer is acquainted. 
In the Braintree, (Mass.) species (P. Harlani, Green) as represented in Dana’s Manual of 
Geology, the eyelobe is short, not extending as far back as the first glabellar furrow; and 
in the Newfoundland species, described by the late Mr E. Billings, the base of the eyelobes 
is on a line with the first glabellar furrow. Through the kindness of Mons. J. Barrande, 
however, the writer has been directed to the figures and descriptions of Bohemian trilobites 
from which it appears that forms with continuous eyelobes are not unknown in Europe. 
In his Silurian System Barrande figures a species, P. rugulosus, Corda, which closely 
resembles one of those I am about to describe, but differs in the shorter posterior margin 
and in the form of the pygidium from any of the species found at St. John. Mons. Barrande 
has also kindly sent to the writer a sketch of a Scandinavian species, of larger size, which 
possesses a continuous eyelobe. This form differs from ours not only in the shape of the 
eyelobe and in other respects, but the peculiar pygidium is very unlike any that are found 
at St. John. Dr. Henry Hicks, to whom I have submitted tracings of our species, does not 
recognize any as known to him in the English Cambrian rocks, and I am therefore led to 
suppose that all the St. John species are new. 
Though having in common this peculiarity of a continuous eyelobe, there is much 
diversity of form in other respects. The glabella varies in outline and height, and in the 
direction and deepness of the furrows, the anterior margin in length and flexure, the 
eyelobe in curve and elevation, the posterior margin in width and direction. Some of 
these differences may be due to age, or to distortion and pressure, but mere variation from 
mechanical causes will not account for all the forms of the glabella, &c., observed in the 
St. John Paradoxides. When, also, the surface markings of the tests and the variety of 
hypostomes, pygidia and moveable cheeks is considered, it is clear that the St. John beds 
contain a number of species of this genus of trilobites. With the imperfect material at 
command, however, the writer is not prepared to describe more than two species, besides 
that already described by the late Prof. C. F. Hartt, as P. lamellatus. Among the glabellæ, 
