new “Worm” from Lower Ludlow Beds. 127 
and ornament becoming obscure. The total length is 69 mm. 
(about 22 inches), It is thus seen that, though the length is 
no greater than the mean length of the American specimens, 
the absolute width is half as much again as in the widest of 
them ; hence the trivial name proposed. 
The segments (fig. 2) are not very convex, but they are 
separated by well-detined grooves, and—asa rule, at any rate— 
each bears two lines of papilla. This at first sight gives the 
appearance of two segments, but the median groove between 
the lines of papillae is less marked than that between the 
segments. In each segment it is frequently the case that 
one line of papille is stouter than the other, so that there is an 
appearance of alternately large and small segments, much as 
in a crinoid stem with alternating columnals. If the feebler 
line of papilla became still slighter or were pushed under the 
next segment, then the appearance would be that of equal 
segments each with a single line of papille. Such is actually 
the appearance towards the ends of the specimen, which there- 
fore in this respect agrees with P, ornatus. In P. magnus 
only one line of papille to the segment has been observed 
throughout. 
No definite arrangement of the papille in longitudinal 
series, either linear or alternating, is immediately obvious ; 
but where the segments are least disturbed and the papille 
most orderly there is a suggestion of oblique lineation, and 
this would probably be plainer if the two lines of papilla 
were of equal strength. 
Where the segments are clearly seen, and the two lines of 
papille fully developed, about four segments occupy 1 mm., 
so that the height of twelve segments equals the width of the 
specimen, 7, e., a ratio about 8/100. The absolute height of the 
segments agrees fairly with that stated for P. ornatus, but. the 
relative height is less than that of any species, the next in 
order being P. magnus. The total number of segments in the 
individual is about 275. Correlated with the greater width of 
the specimen is the increased number of papillz in a line— 
namely, from eighteen to twenty on one side of the compressed 
tube, which is half as many again as in P. ornatus, three 
times as many as in P. magnus. 
The most noteworthy feature of this specimen is a thick- 
ening along the median line, extending through the whole 
curved head of the 2 to within 2°5 mm. of its end, and 
reaching down the stem to a point about 23 mm. from the 
other end. On the imprint, in each counterpart, this thick- 
ening appears as a groove, about 0°5 mm. wide, and of 
roughly semicircular section. In some places the bottom of 
