contracted attitude, and is Hotei hiak : distorted. ‘We ; 
have given, however, models of the head and the tail, ’ 
in two distinct pieces. The external shell, or Atti 
reous covering, is more perfect in this specimen r. 
than in any other we have ever seen. A considera- F 
ble portion of the under side cf the anterior part of © 
the buckler, is also well preserved, and perfectly co- 
incides with the figure and description given of it by 
Dr. Dekay and Mr. Stokes. There is another frag- _ 
ment of an Isotelus in the cabinet of Mr. Wetherill, ; 
showing eight articulations of the abdomen, which ~ 
probably belongs to another individual of this spe- 
cies. The dorsal shell is in a high state of preser- 
vation. ‘This species is embedded in clay slate, and 
was found in Newport, Kentucky. 
Genus Cryprouitruus. Green. 
Among the numerous organic relics embedded 
in black limestone at Trenton Falls, in the State of 
New York, there is often found the fragment of a tri- _ 
lobite which cannot properly be referred to any of © 
the genera already mentioned. Dr. J. Bigsby, in his 
Sketch of the Geology of the Island of Montreal, has ; 
figured and described a fossil which oceurs at that — 
place, which approaches in its specific characters to i 
the fragments found at T renton—but he does not ‘ 
suggest for his relic any name. Professor Brong- | 
a 
% 
niart has also represented, plate 4, figs. 5 and. aA | 
B. C., the fragments of trilobites from Russia and 
from Llandillo, in Wales, which seem to differ but 
