476 
BULLETIN OF THE NATURAL HISTORY SOCIETY 
This species is distinguished from P. elegans by the irregular 
form and relief of the posterior glabellar furrow and the occipital 
furrow, such as may be seen in some Olenidse of the Olenus 
Zone. 
There is a tubercle at the inner end of each posterior glabellar 
furrow and a corresponding pair at the front edge of the 'occipital 
furrow ; these paired tubercles sometimes show on three con- 
secutive somites, viz., at the inner ends of the two posterior pairs 
of glabellar furrows and at the occipital ring. In this view it would 
appear that P. bi-tub crculatus should be regarded as a variety of 
this species in which the paired tubercles of the posterior somite 
of the glabellar are unusually prominent. 
Pr otolenus elegans, w d. m. — This species is more 
abundant than P. paradoxoides but is of a smaller size. Its sur- 
face is minutely tuberculate or granular, or when worn appears 
punctate. The cheeks are always tumid and the front margin 
depressed. The occipital furrow is cut straightfy and evenly 
'across, and the paired tubercles seen on the posterior somites of 
the headsbield in P. iuberculatus , are scarcely ever, and but 
faintly seen on the heads of this species. 
The sculpture is always granular, and the occipital ring direct- 
ly' and smoothly transverse. 
Collections made from the Parade xides lamellatus subzone 
(C.l. c 1 .) gives a lower range for some species common in the 
overlying subzone. 
Paradoxoides Acadicus. Two example of this 
rare species were found in C.l. c.l. it is distinguished by the deep, 
all-across^first and second furrows of the glabella. 
Sculpture . — The inner surface of the glabella is nearly smooth ; 
the outer surface with a strong lens appears minutely granular, but 
in exact focus the sculpture is resolved into very fine concentric 
ridges which are crossed by oblique furrows, giving a granular 
appearance to the surface. The test is thicker than that of 
P. Eteminicus or P. Micmac. The sculpture of concentric ridges 
is faintly discer liable on a test whose middle piece is 9 mm. long. 
Paradoxides Regina. — - An example of a broad flat 
pleura seem to agree best with this large species. It has the 
