ad 
87 
; 
MLE 0 7, 
ger Lf 
age ig 
te, 
Trrarturus Becxir. Green. Cast No. 34. Fig. 6. 
Cauda subrotunda, bipunctatas articulis abdominis 
tribus, absque lobis lateralibus consuetis, sed lobo 
arcuato utrinque apposito. 
The only portions of this fossil which have yet been 
found, are the abdomen, and tail. The abdomen is 
composed of hile, jot the first passes from the 
side lobes complet ely over the body, and on its upper 
surface, near the middle of the back, there is often a 
minuté elevated pimple. The other two, pass ob- 
liquely from the lateral lobes, and are interrug ted in 
their course over the body. The tail, or posterior 
portion, is expanded, something like that of the Iso- 
telus or Dipleura, and, has a deep puncture on each 
side, about half the distance between its terminal 
border and the last articulationof the abdomen. The 
lateral lobes are unlike those of any other genus. 
They form narrow cuniform appendages to the sides3 
near the first joint of the abdomen they are crossed 
transversely by an elevated ridge, from which they 
gradually taper along the sides of the body, and ap- 
pear to’ inosculate in a delicate point at the central 
border of the tail. *Ehe abdominal articulations do 
not pass over these lobes, but Just below the last 
joint, a little transverse furrow, in perfect specimens, 
2S 
may be noticed. The largest specimen of this frag- 
ant I have seen is exactly half an inch in lenge * 
j : ; 
j 
j 
u 
ie 
