48 
In the cabinet of the Albany Institute there are a 
number of specimens of the A. Selenurus. One of 
our models represents the natural mould made by 
the animal in the rock; the other is an impression 
taken from it, in order to exhibit the animal in a 
more satisfactory manner. 
‘ Asapuus LimuLurus.* Green. Cast No. 16. 
Cauda longa, spina munita sicut in Limulo; costis 
abdominis in spinis retrorsum flexis, desinentibus. 
It is very Hh to be reg eretted that the abdomen 
and caudal end only of is. remarkable Asaph have 
hitherto been discovered; it is, however, exceedingly 
gratifying that the fragment still remains in so per- 
fect a state. It forms a part of the magnificent cabi- 
net of organic remains belonging to J. P. Wetherill, 
Esq., now deposited in the Academy of Natural 
Sciences, of Philadelphia. 
Dr. J. J. Cohen discovered a small specimen of 
this species at Lockport, New York, which he has 
presented to the Athenzum, in Baltimore. 6 ite 
Eight articulations of the abdomen, and ten of the 
tail, are all of this fine species that we have seen. 
The ribs, or costal arches of the abdomen have a | 
deep furrow on their upper surface, commencing at 
the middle lobe, and terminating near their free eX: 
tremities; these extremities appear all detatched from 
each other, and end in reflected points or spines, so as 
* From two Greek words, which signify “ Limulus tailed.” 
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